WorldWideScience

Sample records for antithrombin recombinant atryn

  1. Recombinant human antithrombin III: rhATIII.

    Science.gov (United States)

    2004-01-01

    GTC Biotherapeutics (formerly Genzyme Transgenics Corporation) is developing a transgenic form of antithrombin III known as recombinant human antithrombin III [rhATIII]. It is produced by inserting human DNA into the cells of goats so that the targeted protein is excreted in the milk of the female offspring. The transgenic goats have been cloned in collaboration with the Louisiana State University Agriculture Center. GTC Biotherapeutics is conducting clinical trials of rhATIII in coagulation disorders. rhATIII is believed to be both safer and more cost-effective than the currently available plasma-derived product. rhATIII is also being investigated in cancer and acute lung injury. Genzyme Transgenics Corporation, originally a subsidiary of Genzyme Corporation, changed its name to GTC Biotherapeutics in June 2002; it is no longer a subsidiary of Genzyme Corporation. GTC Biotherapeutics is seeking partners for the commercialisation of rhATIII. Restructuring of GTC Biotherapeutics to support its commercialisation programmes was announced in February 2004. Genzyme Transgenics Corporation was developing rhATIII in association with Genzyme General (Genzyme Corporation) in the ATIII LLC joint venture, but in November 2000 a letter of intent was signed for the reacquisition of the rights by Genzyme Transgenics Corporation. It was announced in February 2001 that this reacquisition was not going to be completed and that the development of rhATIII was to continue with ATIII LLC. However, in July 2001, Genzyme Transgenics Corporation reacquired all the rights in the transgenic antithrombin III programme. SMI Genzyme Ltd, a joint venture between Sumitomo Metal Industries, Japan, and Genzyme Transgenics Corporation, USA, was set up to fund development of transgenic antithrombin III in Asia. However, in October 2000, Genzyme Transgenics Corporation reacquired, from Sumitomo Metal Industries, the rights to its technology for production of medicines from milk in 18 Asian countries

  2. Rapid high-performance liquid chromatographic quantification of recombinant human antithrombin III during production and purification

    OpenAIRE

    Büntemeyer, Heino; Tebbe, H.; Lütkemeyer, Dirk; Lehmann, Jürgen

    1994-01-01

    For monitoring of recombinant human antithrombin III during cell culture processes and subsequent purification steps a rapid method for quantitative determination was developed. The need for the introduction of this rapid method came from the limited availability of a quantitative enzyme-linked immunosorbent assay (ELISA) and the very time-consuming ELISA procedure. The developed method is based on reversed-phase high-performance liquid chromatography using a C 4 column. The separation by gra...

  3. The efficacy of recombinant human activated protein C (rhAPC) vs antithrombin III (at III) vs heparin, in the healing process of partial-thickness burns: a comparative study

    Science.gov (United States)

    Kritikos, O.; Tsagarakis, M.; Tsoutsos, D.; Kittas, C.; Gorgoulis, V.; Papalois, A.; Giannopoulos, A.; Kakiopoulos, G.; Papadopoulos, O.

    2012-01-01

    Summary This is an experimental study regarding the positive effect of recombinant human activated protein C (rhAPC) in the healing process of partial-thickness burns, in comparison to antithrombin III and heparin. On a porcine model we induced superficial partial-thickness and deep partial-thickness burns and performed intravenous administration of the elements of study during the first 48 h. The progress of the condition of the injured tissues was evaluated by histopathological examination at specific time intervals. The results showed an improved healing response of the specimens treated with rhAPC compared to those treated with antithrombin III, heparin, and placebo. PMID:23233823

  4. Generation of Humanized Mouse Models with Focus on Antithrombin Deficiency

    DEFF Research Database (Denmark)

    Jensen, Astrid Bøgh

    2015-01-01

    transgene. The CRISPR/Cas9 system is a relatively new and innovative method for targeted mutagenesis. The Cas9 nuclease introduces a double stranded break in the DNA, which can be repaired through homologous recombination of a targeting vector. A mutated Cas9n (Cas9 nickase) has been designed, which only...... gene by the murine antithrombin regulatory sequences, I designed a targeted mutagenesis using the CRISPR/Cas9 system which conserves the 5’UTR of the murine antithrombin gene. With the CRISPR/Cas9 I achieved targeting efficiency for heterozygous integrations of about 80%, which correlated well with our...... preliminary CRISPR/Cas9 experiments targeting the Rosa26 locus. However, when targeting the Rosa26 locus, using the CRISPR/Cas9n system I only observed 65% targeting efficiency for heterozygous integration which correlates well with the requirement for two nicks created by the mutated Cas9n. Others have shown...

  5. Antithrombin, an Important Inhibitor in Blood Clots.

    Science.gov (United States)

    Zhu, Ying; Cong, Qing-Wei; Liu, Yue; Wan, Chun-Ling; Yu, Tao; He, Guang; He, Lin; Cai, Lei; Chou, Kuo-Chen

    2016-01-01

    Blood coagulation is healthy and lifesaving because it can stop bleeding. It can, however, be a troublemaker as well, causing serious medical problems including heart attack and stroke. Body has complex blood coagulation cascade to modulate the blood clots. In the environment of plasma, the blood coagulation cascade is regulated by antithrombin, which is deemed one of the most important serine protease inhibitors. It inhibits thrombin; it can inhibit factors IXa and Xa as well. Interestingly, its inhibitory ability will be significantly increased with the existence of heparin. In this minireview paper, we are to summarize the structural features of antithrombin, as well as its heparin binding modes and anti-coagulation mechanisms, in hopes that the discussion and analysis presented in this paper can stimulate new strategies to find more effective approaches or compounds to modulate the antithrombin. PMID:26411319

  6. Antithrombin III for critically ill patients

    DEFF Research Database (Denmark)

    Afshari, Arash; Wetterslev, Jørn; Brok, Jesper Sune;

    2008-01-01

    Critical illness is associated with uncontrolled inflammation and vascular damage which can result in multiple organ failure and death. Antithrombin III (AT III) is an anticoagulant with anti-inflammatory properties but the efficacy and any harmful effects of AT III supplementation in critically ...

  7. Increased N-glycosylation efficiency by generation of an aromatic sequon on N135 of antithrombin.

    Directory of Open Access Journals (Sweden)

    Sonia Aguila

    Full Text Available The inefficient glycosylation of consensus sequence on N135 in antithrombin explains the two glycoforms of this key anticoagulant serpin found in plasma: α and β, with four and three N-glycans, respectively. The lack of this N-glycan increases the heparin affinity of the β-glycoform. Recent studies have demonstrated that an aromatic sequon (Phe-Y-Asn-X-Thr in reverse β-turns enhances N-glycosylation efficiency and stability of different proteins. We evaluated the effect of the aromatic sequon in this defective glycosylation site of antithrombin, despite of being located in a loop between the helix D and the strand 2A. We analyzed the biochemical and functional features of variants generated in a recombinant cell system (HEK-EBNA. Cells transfected with wild-type plasmid (K133-Y-N135-X-S137 generated 50% of α and β-antithrombin. The S137T, as previously reported, K133F, and the double mutant (K133F/S137T had improved glycosylation efficiency, leading to the secretion of α-antithrombin, as shown by electrophoretic and mass analysis. The presence of the aromatic sequon did not significantly affect the stability of this conformationally sensitive serpin, as revealed by thermal denaturation assay. Moreover, the aromatic sequon hindered the activation induced by heparin, in which is involved the helix D. Accordingly, K133F and particularly K133F/S137T mutants had a reduced anticoagulant activity. Our data support that aromatic sequons in a different structural context from reverse turns might also improve the efficiency of N-glycosylation.

  8. Sulfated cellulose thin films with antithrombin affinity

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Cellulose thin films were chemically modified by in situ sulfation to produce surfaces with anticoagulant characteristics. Two celluloses differing in their degree of polymerization (DP: CEL I (DP 215–240 and CEL II (DP 1300–1400 were tethered to maleic anhydride copolymer (MA layers and subsequently exposed to SO3•NMe3 solutions at elevated temperature. The impact of the resulting sulfation on the physicochemical properties of the cellulose films was investigated with respect to film thickness, atomic composition, wettability and roughness. The sulfation was optimized to gain a maximal surface concentration of sulfate groups. The scavenging of antithrombin (AT by the surfaces was determined to conclude on their potential anticoagulant properties.

  9. Antithrombin III and the nephrotic syndrome.

    Science.gov (United States)

    Jørgensen, K A; Stoffersen, E

    1979-05-01

    Plasma and urinary antithrombin III (AT-III) was measured in 15 cases of nephrotic syndrome. Plasma AT-III correlated well with serum albumin, but poorly with proteinuria, whereas urinary AT-III correlated well to proteinuria. The plasma AT-III level had a mean similar to 25 healthy controls, but the range was significantly wider. A case with nephrotic syndrome and left renal vein thrombosis is reported. The urinary output of AT-III rose and the plasma level fell with the activity of the disease. Although AT-III and albumin have similar molecule weight, their renal clearance was found to be different. It is suggested that urinary loss of AT-III plays a role in the hypercoagulable state sometimes found in the nephrotic syndrome.

  10. 21 CFR 864.7060 - Antithrombin III assay.

    Science.gov (United States)

    2010-04-01

    ... level of antithrombin III (a substance which acts with the anticoagulant heparin to prevent coagulation). This determination is used to monitor the administration of heparin in the treatment of thrombosis....

  11. Cloning, Characterization and Anti-Inflammatory Properties of Bothrops jararaca Snake Antithrombin.

    Science.gov (United States)

    Morais-Zani, Karen de; Grego, Kathleen F; Torquato, Ricardo J S; Silva, Caroline S; Tanaka, Aparecida S; Tanaka-Azevedo, Anita M

    2015-01-01

    Antithrombin inhibits blood coagulation through the interaction with serine proteases in both intrinsic and extrinsic pathways. In addition, antithrombin also shows anti-inflammatory properties, which are independent of its effects on coagulation. This work shows for the first time the cloning and sequencing of antithrombin from a snake species. This predicted protein is composed by 430 amino acids and presents about 64.5% sequence identity to human antithrombin. Biacore experiments revealed that the binding affinity of Bothrops jararaca snake antithrombin to heparin was ~30 times higher than that of human antithrombin. Furthermore, Bothrops jararaca antithrombin is more effective in preventing acute inflammation induced by carrageenan when compared to human antithrombin. Hence, the results showed herein suggest that Bothrops jararaca antithrombin can play a key role in the control of acute inflammation and that this molecule might be used as a pharmacological tool and as a prototype for drug development. PMID:25687119

  12. Molecular basis of antithrombin deficiency in four Japanese patients with antithrombin gene abnormalities including two novel mutations.

    Science.gov (United States)

    Kyotani, Mayu; Okumura, Kaoru; Takagi, Akira; Murate, Takashi; Yamamoto, Koji; Matsushita, Tadashi; Sugimura, Motoi; Kanayama, Naohiro; Kobayashi, Takao; Saito, Hidehiko; Kojima, Tetsuhito

    2007-08-01

    We analyzed the antithrombin (AT) gene in four unrelated Japanese patients with an AT deficiency, and individually identified four distinct mutations in the heterozygous state. There were two novel mutations, 2417delT leading to a frameshift with a premature termination at amino acid -3 (FS-3Stop) and C2640T resulting in a missense mutation (Ala59Val). Previously reported mutations, T5342C (Ser116Pro) and T72C (Met-32Thr), were also found in the other two patients. To understand the molecular basis responsible for the AT deficiency in these patients, in vitro expression experiments were performed using HEK293 cells transfected with either wild type or respective mutant AT expression vector. We found that -3Stop-AT and -32Thr-AT were not secreted into the culture media, whereas 116Pro-AT and 59Val-AT were secreted normally. We further studied the heparin cofactor activity and the binding to heparin of each recombinant AT molecule. Ser116Pro mutation significantly impaired the binding affinity to heparin resulting in a reduced heparin cofactor activity. In contrast, we found that Ala59Val mutant AT unexpectedly showed a normal affinity to heparin, but severely impaired the heparin cofactor activity. Our findings suggested that FS-3Stop and Met-32Thr mutations are responsible for type I AT deficiency, whereas Ser116Pro and Ala59Val mutations contribute to type II AT deficiency, confirming that there were diverse molecular mechanisms of AT deficiency depend upon discrete AT gene abnormalities as reported previously.

  13. Inherited antithrombin deficiency and end stage renal disease.

    Science.gov (United States)

    Hara, Tomohiko; Naito, Katsusuke

    2005-11-01

    Antithrombin is a potent inhibitor of the coagulant effect of thrombin. In the latter half of 20th century, many families have been described in which an autosomaly dominant inherited antithrombin deficiency has caused severe venous thromboembolic disease in successive generations. The important complication is severe venoocclusive disease by deep venous thrombus. Some inherited antithrombin deficient patients developed renal failure because of fibrin deposition in the kidney glomeruli or renal vein thrombus, and therefore the need for replacement therapy for end stage renal disease (ESRD). Although an inherited antithrombin deficiency with renal failure is rare, prevention against renal failure in such patients, and their renal replacement therapy for ESRD are important. Proteinuria decreases plasma antithrombin level leading to more severe hyper-coagulation state. Therefore early in renal disease, it may be prudent for adaptation of anti-coagulation therapy even if recurrent thrombosis has not occurred. All replacement therapy (hemodialysis, transplantation or peritoneal dialysis) for ESRD are available for such thrombophilic disorders. Anticoagulation agents working without aggravation of antithrombin effects (Argatroban, Nafamostat mesilate etc.) are useful for hemodialysis. The renal allograft recipients with thrombophilia seem to be at risk of developing an acute rejection or other vascular event. Peritoneal dialysis is potentially a good adaptation for such thrombophilic disorders. However which therapy has the best mortality and morbidity outcomes is not clear. Physicians and Surgeons must pay attention to the coagulation state and thrombophilia in ESRD patients, give strong consideration for adequate anti-coagulation therapy and review the best renal replacement modality for each patient.

  14. [Antithrombin resistance: a new mechanism of inherited thrombophilia].

    Science.gov (United States)

    Kojima, Tetsuhito; Takagi, Akira; Murata, Moe; Takagi, Yuki

    2015-06-01

    Venous thromboembolism is a multifactorial disease resulting from complex interactions among genetic and environmental factors. To date, numerous genetic defects have been found in families with hereditary thrombophilia, but there may still be many undiscovered causative gene mutations. We investigated a possible causative gene defect in a large Japanese family with inherited thrombophilia, and found a novel missense mutation in the prothrombin gene (p.Arg596Leu) resulting in a variant prothrombin (prothrombin Yukuhashi). The mutant prothrombin had moderately lower activity than wild type prothrombin in clotting assays, but formation of the thrombin-antithrombin (TAT) complex was substantially impaired resulting in prolonged thrombin activity. A thrombin generation assay revealed that the peak activity of the mutant prothrombin was fairly low, but its inactivation was extremely slow in reconstituted plasma. The Leu596 substitution caused a gain-of-function mutation in the prothrombin gene, resulting in resistance to antithrombin and susceptibility to thrombosis. We also showed the effects of the prothrombin Yukuhashi mutation on the thrombomodulin-protein C anticoagulation system, recent development of a laboratory test detecting antithrombin resistance in plasma, and another antithrombin resistant mutation found in other thrombophilia families. PMID:26256872

  15. Inherited antithrombin deficiency and anabolic steroids: a risky combination.

    Science.gov (United States)

    Choe, Hannah; Elfil, Mohamed; DeSancho, Maria T

    2016-09-01

    A 20-year-old male with asymptomatic inherited type 1 antithrombin deficiency and a family history of thrombosis started injecting himself with testosterone 250 mg intramuscularly twice weekly for 5 weeks. He presented to the hospital with progressive dyspnea on exertion, chest pain and hemoptysis. Workup revealed bilateral submassive pulmonary embolism and proximal right lower extremity deep vein thrombosis. He was treated with intravenous (IV) unfractionated heparin and underwent catheter-directed thrombolysis with alteplase to the main pulmonary arteries. Postprocedure, he remained on IV alteplase infusion for 24 h and unfractionated heparin in the intensive care unit. Concomitantly he received plasma-derived antithrombin concentrate. He was transitioned to subcutaneous enoxaparin twice daily and discharged from the hospital on oral rivaroxaban 15 mg twice a day. This case highlights the heightened thrombogenic effect of anabolic steroids in the setting of underlying thrombophilia especially in younger subjects. PMID:26588446

  16. Interaction of antithrombin III with preadsorbed albumin-heparin conjugates

    OpenAIRE

    Hennink, W.E.; Ebert, C.D.; Kim, S. W.; Breemhaar, W.; Bantjes, A.; Feijen, J.

    1984-01-01

    The adsorption of antithrombin III (AT III) onto polystyrene surfaces preadsorbed with albumin or albuminheparin conjugates was studied using a two step enzyme immuno assay. When AT III-buffer solutions were used, the highest adsorption values were measured on high affinity albumin-heparin conjugate pretreated surfaces. Less AT III adsorption was found on nonfractionated albumin-heparin conjugate preadsorbed surfaces. AT III adsorption could also be detected on low affinity conjugate and albu...

  17. Present and future of anticoagulant therapy using antithrombin and thrombomodulin for sepsis-associated disseminated intravascular coagulation: a perspective from Japan.

    Science.gov (United States)

    Iba, Toshiaki; Thachil, Jecko

    2016-03-01

    In sepsis, the coagulation system is often systemically activated in combination with the simultaneous impairment of fibrinolysis and anticoagulant systems. Since this hypercoagulable state often leads to disseminated intravascular coagulation (DIC), an independent predictor of mortality in critically ill patients, the appropriate management of DIC itself is a crucial part of treatment strategies for severe sepsis. In this context, the Japanese Association of Acute Medicine (JAAM) scoring system for DIC has been proposed as a valid test for diagnosing DIC; this system is also expected to aid in devising specifically tailored management strategies. Anticoagulant therapy is commonly given to septic patients with DIC as part of the standard care in Japan. More recently, antithrombin concentrate and recombinant thrombomodulin have become the two major anticoagulant agents of choice. In relation to the use of antithrombin, recent studies have indicated that the recovery of antithrombin activity to within the normal range (>70%) is necessary if supplementation therapy is to provide a favorable outcome. Recombinant thrombomodulin is slightly more controversial, with favorable results being greater among severe cases of DIC. In the present review, we summarize recent clinical advances in anticoagulant therapy for sepsis-associated DIC. PMID:26588929

  18. Portal vein thrombosis treated using danaparoid sodium and antithrombin III.

    Science.gov (United States)

    Uchiyama, T; Hirokazu, Takahashi; Hosono, K; Endo, H; Akiyama, T; Yoneda, K; Inamori, M; Abe, Y; Kubota, K; Saito, S; Nakajima, A

    2010-01-01

    A 45-year-old man under treatment for liver cirrhosis (LC) due to chronic hepatitis C and hemophilia A was seen in our emergency room because of a 10-kg weight gain in the previous week due to ascites. Portal vein thrombosis (PVT) was detected with computer tomography (CT) and ultrasonographic (US). Danaparoid sodium (DS) and antithrombin III (AT III) were administrated and doppler US images showed improvement of portal venous blood flow. DS or AT III may be safe and alternative therapies for PVT. PMID:20422871

  19. Identification of Regulatory Mutations in SERPINC1 Affecting Vitamin D Response Elements Associated with Antithrombin Deficiency

    Science.gov (United States)

    Toderici, Mara; de la Morena-Barrio, María Eugenia; Padilla, José; Miñano, Antonia; Antón, Ana Isabel; Iniesta, Juan Antonio; Herranz, María Teresa; Fernández, Nuria; Vicente, Vicente; Corral, Javier

    2016-01-01

    Antithrombin is a crucial anticoagulant serpin whose even moderate deficiency significantly increases the risk of thrombosis. Most cases with antithrombin deficiency carried genetic defects affecting exons or flanking regions of SERPINC1.We aimed to identify regulatory mutations inSERPINC1 through sequencing the promoter, intron 1 and 2 of this gene in 23 patients with antithrombin deficiency but without known genetic defects. Three cases with moderate antithrombin deficiency (63–78%) carried potential regulatory mutations. One located 200 bp before the initiation ATG and two in intron 1. These mutations disrupted two out of five potential vitamin D receptor elements (VDRE) identified in SERPINC1 with different software. One genetic defect, c.42-1060_-1057dupTTGA, was a new low prevalent polymorphism (MAF: 0.01) with functional consequences on plasma antithrombin levels. The relevance of the vitamin D pathway on the regulation of SERPINC1 was confirmed in a cell model. Incubation of HepG2 with paricalcitol, a vitamin D analog, increased dose-dependently the levels of SERPINC1transcripts and antithrombin released to the conditioned medium. This study shows further evidence of the transcriptional regulation of SERPINC1 by vitamin D and first describes the functional and pathological relevance of mutations affecting VDRE of this gene. Our study opens new perspectives in the search of new genetic defects involved in antithrombin deficiency and the risk of thrombosis as well as in the design of new antithrombotic treatments. PMID:27003919

  20. Antithrombin gene Arg197Stop mutation-associated venous sinus thrombosis in a Chinese family

    Institute of Scientific and Technical Information of China (English)

    Ang Li; Dexin Wang; Qiming Xue; Baoen Wang; Tianhui Liu; Zhandong Liu; Jimei Li; Chunling Zhang; Jun Chen; Jinmei Sun; YanfeiHan; Lili Wang

    2011-01-01

    This study sought to elucidate the genetic correlation of cerebral venous sinus thrombosis caused by a hereditary antithrombin deficiency in a Chinese family, at the genetic and protein levels. A nonsense mutation from C to T on locus 6431 in exon 3B of the antithrombin gene was observed,leading to an arginine (CGA) to stop codon (TGA) change in the protein. This is the first report of this mutation in China. Ineffective heparin therapy in the propositus patient is associated with a lack of heparin binding sites after antithrombin gene mutation. Characteristic low intracranial pressure in the acute phase might be specific to this patient with cerebral venous sinus thrombosis.

  1. [Discovery and prospects of a novel thrombophilia: antithrombin resistance].

    Science.gov (United States)

    Takagi, Yuki; Kojima, Tetsuhito

    2014-07-01

    Pathogenesis of venous thromboembolism (VTE) known to be complex and multifactorial process involves the interaction of acquired factors and genetic predisposing conditions. Deficiency of natural anticoagulant factors such as antithrombin (AT), protein C and protein S increases the risk of a VTE. Recently, we have reported novel mechanism of hereditary thrombosis in a Japanese family, in which AT resistance was associated with a missense mutation (p.Arg596Leu) in the prothrombin gene named prothrombin Yukuhashi. The mutant thrombin showed a low clotting activity, but a severely impaired inactivation by AT, resulting in a susceptibility to thrombosis. We have developed a new laboratory test to evaluate AT resistance in plasma. Prothrombin mutation causing AT resistance has found in Caucasian, not only in Japanese. PMID:25163329

  2. Clinical review: molecular mechanisms underlying the role of antithrombin in sepsis.

    Science.gov (United States)

    Wiedermann, Christian J

    2006-02-01

    In disseminated intravascular coagulation (DIC) there is extensive crosstalk between activation of inflammation and coagulation. Endogenous anticoagulatory pathways are downregulated by inflammation, thus decreasing the natural anti-inflammatory mechanisms that these pathways possess. Supportive strategies aimed at inhibiting activation of coagulation and inflammation may theoretically be justified and have been found to be beneficial in experimental and initial clinical studies. This review assembles the available experimental and clinical data on biological mechanisms of antithrombin in inflammatory coagulation activation. Preclinical research has demonstrated partial interference of heparin--administered even at low doses--with the therapeutic effects of antithrombin, and has confirmed--at the level of cellular mechanisms--a regulatory role for antithrombin in DIC. Against this biological background, re-analyses of data from randomized controlled trials of antithrombin in sepsis suggest that antithrombin has the potential to be developed further as a therapeutic agent in the treatment of DIC. Even though there is a lack of studies employing satisfactory methodology, the results of investigations conducted thus far into the mechanisms of action of antithrombin allow one to infer that there is biological plausibility in the value of this agent. Final assessment of the drug's effectiveness, however, must await the availability of positive, prospective, randomized and placebo-controlled studies. PMID:16542481

  3. Antithrombin Ⅲ injection via the portal vein suppresses liver damage

    Institute of Scientific and Technical Information of China (English)

    Masavuki Mivazaki; Kazuhiro Kotoh; Ryoichi Takayanagi; Masaki Kato; Masatake Tanaka; Kosuke Tanaka; Shinichiro Takao; Motoyuki Kohjima; Tetsuhide Ito; Munechika Enjoji; Makoto Nakamuta

    2012-01-01

    AIM:To investigate the effects of antithrombin Ⅲ (AT Ⅲ) injection via the portal vein in acute liver failure.METHODS:Thirty rats were intraperitoneally challenged with lipopolysaccharide (LPS) and D-galactosamine (GaiN) and divided into three groups:a control group; a group injected with AT Ⅲ via the tail vein; and a group injected with AT Ⅲ via the portal vein.AT Ⅲ (50U/kg body weight) was administrated 1 h after challenge with LPS and GAIN.Serum levels of inflammatory cytokines and fibrin degradation products,hepatic fibrin deposition,and hepatic mRNA expression of hypoxiarelated genes were analyzed.RESULTS:Serum levels of alanine aminotransferase,tumor necrosis factor-o and interleukin-6 decreased significantly following portal vein AT Ⅲ injection compared with tail vein injection,and control rats.Portal vein AT Ⅲ injection reduced liver cell destruction and decreased hepatic fibrin deposition.This treatment also significantly reduced hepatic mRNA expression of lactate dehydrogenase and heme oxygenase-1.CONCLUSION:A clinically acceptable dose of AT Ⅲ injection into the portal vein suppressed liver damage,probably through its enhanced anticoagulant and antiinflammatory activities.

  4. Supplemental dose of antithrombin use in disseminated intravascular coagulation patients after abdominal sepsis.

    Science.gov (United States)

    Tagami, Takashi; Matsui, Hiroki; Fushimi, Kiyohide; Yasunaga, Hideo

    2015-08-31

    The effectiveness of supplemental dose antithrombin administration (1,500 to 3,000 IU/ day) for patients with sepsis-associated disseminated intravascular coagulation (DIC), especially sepsis due to abdominal origin, remains uncertain. This was a retrospective cohort study of patients with mechanically ventilated septic shock and DIC after emergency surgery for perforation of the lower intestinal tract using a nationwide administrative database, Japanese Diagnosis Procedure Combination inpatient database. A total of 2,164 patients treated at 612 hospitals during the 33-month study period between 2010 and 2013 were divided into an antithrombin group (n=1,021) and a control group (n=1,143), from which 518 propensity score-matched pairs were generated. Although there was no significant 28-day mortality difference between the two groups in the unmatched groups (control vs antithrombin: 25.7 vs 22.9 %; difference, 2.8 %; 95 % confidence interval [CI], -0.8-6.4), a significant difference existed between the two groups in propensity-score weighted groups (26.3 vs 21.7 %; difference, 4.6 %; 95 % CI, 2.0-7.1) and propensity-score matched groups (27.6 vs 19.9 %; difference, 7.7 %; 95 % CI, 2.5-12.9). Logistic regression analyses showed a significant association between antithrombin use and lower 28-day mortality in propensity-matched groups (odds ratio, 0.65; 95 % CI, 0.49-0.87). Analysis using the hospital antithrombin-prescribing rate as an instrumental variable showed that receipt of antithrombin was associated with a 6.5 % (95 % CI, 0.05-13.0) reduction in 28-day mortality. Supplemental dose of antithrombin administration may be associated with reduced 28-day mortality in sepsis-associated DIC patients after emergency laparotomy for intestinal perforation.

  5. Relationship between renal histology and plasma antithrombin III activity in women with early onset preeclampsia.

    Science.gov (United States)

    Weiner, C P; Bonsib, S M

    1990-04-01

    Renal biopsy was performed in 12 women with the clinical diagnosis of severe, early-onset preeclampsia at the time of cesarean delivery for the express purpose of aiding future counseling on the risk of recurrence. The mean gestation at delivery was 30 +/- 3 weeks. The mean birthweight was 1090 +/- 505 gm. Four women (33%) were multiparous. Antithrombin III activity was determined immediately prior to delivery unrelated to clinical care and as part of other protocols. The biopsy was performed without difficulty in each, although the sample was inadequate in one patient. The clinical diagnosis of preeclampsia was confirmed in nine (82%). However, three of the nine had underlying renal disease, as did the two women without histologic evidence of preeclampsia (42% of the total). Correlations between laboratory parameters with the histopathologic diagnoses were sought. Neither uric acid, creatinine, blood urea nitrogen, platelet count, or 24-hour urinary protein measurements aided the differentiation of the various subgroups. Antithrombin III activity in women with biopsy-supported preeclampsia (77% +/- 12%) was significantly lower than that in women without histologic evidence of preeclampsia (116% +/- 8%). Antithrombin III activity correctly predicted biopsy findings in at least 9 of 11 (82%). These preliminary findings confirm the high frequency of underlying disease in women with early-onset preeclampsia. Although low antithrombin III activity does not differentiate between "pure" preeclampsia and superimposed disease, a normal antithrombin III activity is reassuring and more consistent with a nonpreeclamptic renal complication than with preeclampsia.

  6. Change of Coagulation Factor Ⅷ and Antithrombin Ⅲ Activity in Bank-Stored Blood

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Coagulation factor Ⅷ and antithrombin Ⅲ activity were detected in 15 health donors. It was found that antithrombin Ⅲ activity decreased obviously 12 h after blood drawing. It lost 56 % of the activity at the 3rd day, and 70 % of the activity at the 7th day. FⅧ:c showed no obvious change after 24 h, until the 3rd day. It lost 40 %-60 % of the activity after 36 h and was reduced to the 30 % of the original activity at the 5th day. Our results suggested that at the 3rd day coagulation factor Ⅷ of bank-stored blood can be used to replenish antithrombin Ⅲ, while bank-stored blood in one day can be used to replenish FⅧ.

  7. Biochemical activity and gene analysis of inherited protein C and antithrombin deficiency in two Chinese pedigrees

    Institute of Scientific and Technical Information of China (English)

    周荣富; 傅启华; 王文斌; 谢爽; 胡翊群; 王学锋; 王振义; 王鸿利

    2004-01-01

    Background We identified the gene mutations in two Chinese pedigree of type Ⅰ hereditary protein C deficiency and type Ⅰ hereditary antithrombin deficiency.Methods The plasma level of protein C activity (PC∶ A), protein C antigen (PC∶ Ag) , protein S activity, antithrombin activity (AT∶ A) and antithrombin antigen (AT∶ Ag) of propositi and two family members were detected using ELISA and chromogenic assay, respectively. All exons and intron-exon boundaries of protein C gene and antithrombin gene were analyzed by direct sequencing of the corresponding amplified PCR products in DNA from the propositus. Results The plasma PC∶ A and PC∶ Ag of propositus 1 was 26% and 1.43 mg/dl, respectively. The PC∶ Ag and PC∶ A of his father were normal. The decreased PC∶ A level was seen in his mother and 4 of his maternal pedigree. PS∶ A and AT∶ A were all normal in pedigree 1 members. A C5498T heterozygous mutation in exon 3 of protein C gene, resulting in the substitution of Arg for Trp at the 15th amino acid, was identified in propositus 1 and 8 of his relatives. The plasma AT∶ A and AT∶ Ag of propositus 2 was 48.6% and 10.4 mg/dl, respectively. The reduced AT∶ A and AT∶ Ag levels were found in his father and 5 of paternal pedigree. PC∶ A, PC∶ Ag and PS∶ A were all in normal range. A heterozygous 13387-9G deletion in exon 6 of antithrombin gene was identified in propositus 2. This mutation introduced a frameshift and a premature stop at codon 426 and existed in 6 members of pedigree 2.Conclusion The C5498T heterozygous mutation in exon 3 of protein C gene, first reported in China, leads to type I hereditary protein C deficiency. The 13387-9G deletion, a novel mutation, can cause antithrombin deficiency and thrombosis.

  8. Antithrombin Cambridge II(A384S) mutation frequency and antithrombin activity levels in 120 of deep venous thrombosis and 150 of cerebral infarction patients in a single center in Southern China.

    Science.gov (United States)

    Zhang, Guang-sen; Tang, Yang-ming; Tang, Mei-qing; Qing, Zi-Ju; Shu, Chang; Tang, Xiang-qi; Deng, Ming-yang; Tan, Li-ming

    2010-09-01

    Antithrombin Cambridge II(A384S) mutation shows a relatively high frequency in western population. Some studies suggest that the mutation is an independent genetic risk factor both for deep vein thrombosis (DVT) and for arterial thrombosis, but whether the mutation has racial difference or has a general significance for thrombophilia remains unclear. In this study we performed an analysis of the prevalence of the mutation in Chinese southern population; Also, the antithrombin activity levels were evaluated in each investigated individual. The studies included 120 patients with DVT, 150 patients with cerebral infarction, and 110 controls. The mutation was detected using polymerase chain reaction/PvuII restrictive fragment length polymorphism procedures. Antithrombin activity assay was done using chromogenic substrate method. The results showed that no antithrombin Cambridge II mutation was detected in all three groups (DVT, cerebral infarction and controls), the incidence was 0/380. Plasma antithrombin activity was 91.37% +/- 16.15% in the DVT patients and 102.68% +/- 13.10% in the controls; the antithrombin activity was significantly reduced in the DVT group (P Cambridge II mutation has a racial difference, and may not be a valuable risk factor of thrombophilia in Asian population, and antithrombin deficiency remains a major genetic risk factor for DVT patients in China.

  9. Effect of fibronectin on the binding of antithrombin III to immobilized heparin

    NARCIS (Netherlands)

    Byun, Youngro; Jacobs, Harvey A.; Feijen, Jan; Kim, Sung Wan

    1996-01-01

    An objective of this research is to verify the mechanism of anticoagulant activity of surface-immobilized heparin in the presence of plasma proteins. The competition and binding interaction between immobilized heparin and antithrombin III (ATIII)/thrombin have been described in vitro. However, the s

  10. Activation of antithrombin III isoforms by heparan sulphate glycosaminoglycans and other sulphated polysaccharides.

    Science.gov (United States)

    Carlson, T H; Kolman, M R; Piepkorn, M

    1995-07-01

    Antithrombin III occurs naturally as two functionally distinct molecular species that differ in glycosylation at Asn135. Whereas the predominant, glycosylated isoform has high affinity for heparin, a quantitatively minor isoform lacking glycosylation at that site displays relatively higher affinity for both heparins and heparinoids. We characterized the ability of various sulphated polysaccharides to potentiate the rates of thrombin inhibition by the isoforms. High-molecular-weight dextran sulphate was the most effective of those studied, increasing thrombin inhibition by the higher-affinity antithrombin III isoform up to five-fold more efficiently than did heparin fractions with low-affinity for antithrombin III. In addition, dextran sulphate activated the higher-affinity isoform as much as twelve times more effectively than it did the lower-affinity isoform. Pentosan polysulphate was up to three-fold, and some heparan sulphate fractions up to two-fold, more effective with the higher, compared with the lower affinity, isoform. Heparan sulphate preparations less effectively increased the rate of thrombin inhibition than did the other low-affinity polysaccharides. Structure-function studies indicated positive correlations between activity and both polymer length and anionic group density of low-affinity sulphated polysaccharides. The observed effects of the heparan sulphates on this anticoagulant pathway, although of low potency, are consistent with the hypotheses that these substances naturally regulate blood homeostasis in vascular tissues and that much of this function may be mediated by the higher-affinity antithrombin III isoform. PMID:8589216

  11. Anticoagulant and anti-inflammatory effects after peritoneal lavage with antithrombin in experimental polymicrobial peritonitis

    NARCIS (Netherlands)

    S.Q. van Veen; C.W. Cheung; J.C.M. Meijers; T.M. van Gulik; M.A. Boermeester

    2006-01-01

    Background: In sepsis, coagulation inhibition using high-dose systemic antithrombin (AT) tends to improve survival. However, systemic AT use is complicated by increased risk of bleeding (odds ratio 1,7) and clinically important survival increase is seen only in the non-heparinized subgroup. Local (i

  12. Antithrombin inhibits bronchoalveolar activation of coagulation and limits lung injury during Streptococcus pneumoniae pneumonia in rats

    NARCIS (Netherlands)

    Choi, Goda; Hofstra, Jorrit-Jan H; Roelofs, Joris J T H; Rijneveld, Anita W; Bresser, Paul; van der Zee, Jaring S; Florquin, Sandrine; van der Poll, Tom; Levi, Marcel; Schultz, Marcus J

    2008-01-01

    OBJECTIVE: Alveolar fibrin deposition is a hallmark of pneumonia. It has been proposed that natural inhibitors of coagulation, including activated protein C, antithrombin, and tissue factor pathway inhibitor, exert lung-protective effects via anticoagulant and possibly anti-inflammatory pathways. We

  13. Identification of antithrombin-modulating genes. Role of LARGE, a gene encoding a bifunctional glycosyltransferase, in the secretion of proteins?

    Directory of Open Access Journals (Sweden)

    María Eugenia de la Morena-Barrio

    Full Text Available The haemostatic relevance of antithrombin together with the low genetic variability of SERPINC1, and the high heritability of plasma levels encourage the search for modulating genes. We used a hypothesis-free approach to identify these genes, evaluating associations between plasma antithrombin and 307,984 polymorphisms in the GAIT study (352 individuals from 21 Spanish families. Despite no SNP reaching the genome wide significance threshold, we verified milder positive associations in 307 blood donors from a different cohort. This validation study suggested LARGE, a gene encoding a protein with xylosyltransferase and glucuronyltransferase activities that forms heparin-like linear polysaccharides, as a potential modulator of antithrombin based on the significant association of one SNPs, rs762057, with anti-FXa activity, particularly after adjustment for age, sex and SERPINC1 rs2227589 genotype, all factors influencing antithrombin levels (p = 0.02. Additional results sustained this association. LARGE silencing inHepG2 and HEK-EBNA cells did not affect SERPINC1 mRNA levels but significantly reduced the secretion of antithrombin with moderate intracellular retention. Milder effects were observed on α1-antitrypsin, prothrombin and transferrin. Our study suggests LARGE as the first known modifier of plasma antithrombin, and proposes a new role for LARGE in modulating extracellular secretion of certain glycoproteins.

  14. Identification of Antithrombin-Modulating Genes. Role of LARGE, a Gene Encoding a Bifunctional Glycosyltransferase, in the Secretion of Proteins?

    Science.gov (United States)

    de la Morena-Barrio, María Eugenia; Buil, Alfonso; Antón, Ana Isabel; Martínez-Martínez, Irene; Miñano, Antonia; Gutiérrez-Gallego, Ricardo; Navarro-Fernández, José; Aguila, Sonia; Souto, Juan Carlos; Vicente, Vicente; Soria, José Manuel; Corral, Javier

    2013-01-01

    The haemostatic relevance of antithrombin together with the low genetic variability of SERPINC1, and the high heritability of plasma levels encourage the search for modulating genes. We used a hypothesis-free approach to identify these genes, evaluating associations between plasma antithrombin and 307,984 polymorphisms in the GAIT study (352 individuals from 21 Spanish families). Despite no SNP reaching the genome wide significance threshold, we verified milder positive associations in 307 blood donors from a different cohort. This validation study suggested LARGE, a gene encoding a protein with xylosyltransferase and glucuronyltransferase activities that forms heparin-like linear polysaccharides, as a potential modulator of antithrombin based on the significant association of one SNPs, rs762057, with anti-FXa activity, particularly after adjustment for age, sex and SERPINC1 rs2227589 genotype, all factors influencing antithrombin levels (p = 0.02). Additional results sustained this association. LARGE silencing inHepG2 and HEK-EBNA cells did not affect SERPINC1 mRNA levels but significantly reduced the secretion of antithrombin with moderate intracellular retention. Milder effects were observed on α1-antitrypsin, prothrombin and transferrin. Our study suggests LARGE as the first known modifier of plasma antithrombin, and proposes a new role for LARGE in modulating extracellular secretion of certain glycoproteins. PMID:23705025

  15. Mechanism of poly(acrylic acid) acceleration of antithrombin inhibition of thrombin: implications for the design of novel heparin mimics.

    Science.gov (United States)

    Monien, Bernhard H; Cheang, Kai I; Desai, Umesh R

    2005-08-11

    The bridging mechanism of antithrombin inhibition of thrombin is a dominant mechanism contributing a massive approximately 2500-fold acceleration in the reaction rate and is also a key reason for the clinical usage of heparin. Our recent study of the antithrombin-activating properties of a carboxylic acid-based polymer, poly(acrylic acid) (PAA), demonstrated a surprisingly high acceleration in thrombin inhibition (Monien, B. H.; Desai, U. R. J. Med. Chem. 2005, 48, 1269). To better understand this interesting phenomenon, we have studied the mechanism of PAA-dependent acceleration in antithrombin inhibition of thrombin. Competitive binding studies with low-affinity heparin and a heparin tetrasaccharide suggest that PAA binds antithrombin in both the pentasaccharide- and the extended heparin-binding sites, and these results are corroborated by molecular modeling. The salt-dependence of the K(D) of the PAA-antithrombin interaction shows the formation of five ionic interactions. In contrast, the contribution of nonionic forces is miniscule, resulting in an interaction that is significantly weaker than that observed for heparins. A bell-shaped profile of the observed rate constant for antithrombin inhibition of thrombin as a function of PAA concentration was observed, suggesting that inhibition proceeds through the "bridging" mechanism. The knowledge gained in this mechanistic study highlights important rules for the rational design of orally available heparin mimics. PMID:16078853

  16. An Antithrombin-Heparin Complex Increases the Anticoagulant Activity of Fibrin Clots

    Directory of Open Access Journals (Sweden)

    Lesley J. Smith

    2008-01-01

    Full Text Available Clotting blood contains fibrin-bound thrombin, which is a major source of procoagulant activity leading to clot extension and further activation of coagulation. When bound to fibrin, thrombin is protected from inhibition by antithrombin (AT + heparin but is neutralized when AT and heparin are covalently linked (ATH. Here, we report the surprising observation that, rather than yielding an inert complex, thrombin-ATH formation converts clots into anticoagulant surfaces that effectively catalyze inhibition of thrombin in the surrounding environment.

  17. Comparison of antithrombin activity of the polysulphate chitosan derivatives in in vivo and in vitro system.

    Science.gov (United States)

    Drozd, N N; Sher, A I; Makarov, V A; Galbraikh, L S; Vikhoreva, G A; Gorbachiova, I N

    2001-06-01

    In order to choose the proper method for evaluating the antithrombin activity in samples of chitosan polysulphate (CP) with different polymerization degrees and sulphation degrees, we estimated the ability of direct anticoagulants to depress the coagulability of recalcified sheep blood using the third international heparin standard (A1 - in vitro system) and determined such activity on pharmacodynamic curve (A2 - in vivo system). The curve admits the kinetics of CP elimination to be nonlinear in case of intravenous injection to rabbits, as it is observed in heparin: Ct = C(o)exp(-K(e)lt), where Ct is the CP concentration at the time moment t; C(o) is the CP concentration at the injection moment; Kel is the elimination constant. Besides, it is assumed that there is a linear approximation of the anticoagulant effect on the dose, which finally makes it possible to calculate the specific activity A2: T = KTCt+T(in), where T is the time of clot formation at different time intervals after CP injection; T(in) is the time of clot formation prior to CP injection. T value was assessed in two tests: blood coagulation time (BCT) and activated partial thromboplastin time (APTT). No correlation was observed between A1 and A2. At the same time, the values of Kel and the period of semi-elimination, with the use of the biospecific cetylpyridinium chloride electrophores for the quantitative determination of CP in rabbit's blood taken at different time intervals after injection, showed a close correlation (r = .94, P < .05) between the same parameters, obtained with the help of the rectilinear pharmacodynamic plot in BCT test. Thus, experimentally, it was proven that the assumption of the CP nonlinear elimination and the CP effect-dose dependence was true, which is necessary for A2 calculation. Relatively low molecular weights (MW 61-82 kDa, polymerization degree 188-252 ) and high sulphation patterns (sulphur amounts 15.6-16.9%, sulphation degree 1.58-1.86) were slowly cleared and

  18. Dynamic properties of the native free antithrombin from molecular dynamics simulations: computational evidence for solvent- exposed Arg393 side chain.

    Science.gov (United States)

    Tóth, László; Fekete, Attila; Balogh, Gábor; Bereczky, Zsuzsanna; Komáromi, István

    2015-09-01

    While antithrombin (AT) has small basal inhibitory activity, it reaches its full inhibitory potential against activated blood coagulation factors, FXa, FIXa, and FIIa (thrombin), via an allosteric and/or template (bridging) mechanism by the action of heparin, heparan sulfate, or heparin-mimetic pentasaccharides (PS). From the numerous X-ray structures available for different conformational states of AT, only indirect and incomplete conclusions can be drawn on the inherently dynamic properties of AT. As a typical example, the basal inhibitory activity of AT cannot be interpreted on the basis of "non-activated" free antithrombin X-ray structures since the Arg393 side chain, playing crucial role in antithrombin-proteinase interaction, is not exposed. In order to reveal the intrinsic dynamic properties and the reason of basal inhibitory activity of antithrombin, 2 μs molecular dynamics simulations were carried out on its native free-forms. It was shown from the simulation trajectories that the reactive center loop which is functioning as "bait" for proteases, even without any biasing potential can populate conformational state in which the Arg393 side chain is solvent exposed. It is revealed from the trajectory analysis that the peptide sequences correspond to the helix D extension, and new helix P formation can be featured with especially large root-mean-square fluctuations. Mutual information analyses of the trajectory showed remarkable (generalized) correlation between those regions of antithrombin which changed their conformations as the consequence of AT-PS complex formation. This suggests that allosteric information propagation pathways are present even in the non-activated native form of AT. PMID:25483839

  19. Polyurethane films modified by antithrombin-heparin complex to enhance endothelialization: An original impedimetric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, S.; Zanina, N. [Biophysic Laboratory, Faculty of Medicine of Monastir, 5019 Monastir (Tunisia) and INSERM U 698 Laboratoire de Bio-Ingenierie de Polymeres Cardiovasculaires, Universite Paris 13, 99, av JB Clement, Institut Galilee, 93430 Villetaneuse (France); Othmane, A. [Biophysic Laboratory, Faculty of Medicine of Monastir, 5019 Monastir (Tunisia); Mora, L., E-mail: Laurence.mora@univ-paris13.fr [INSERM U 698 Laboratoire de Bio-Ingenierie de Polymeres Cardiovasculaires, Universite Paris 13, 99, av JB Clement, Institut Galilee, 93430 Villetaneuse (France)

    2011-08-30

    In this paper, polyurethane (PU) was deposited as a thin layer onto the surface of ITO (indium tin oxide) and was then modified with an antithrombin-heparin complex (ATH). The resulting films were characterized by ATR spectroscopy, contact angle measurements and electrochemical impedance spectroscopy (EIS). Physicochemical characterization confirmed the surface modifications. The obtained films were used as substrates for endothelial cell attachment and growth. These processes were characterized using electrochemical impedance spectroscopy (EIS). We observed that the addition of a small amount of heparin and AT additives onto the polymer surface resulted in a considerable change in the surface characteristics, and we found that PU films that were modified by the ATH complex were able to greatly enhance adhesion and proliferation of endothelial cells (ECs).

  20. Is there evidence that fresh frozen plasma is superior to antithrombin administration to treat heparin resistance in cardiac surgery?

    Science.gov (United States)

    Beattie, Gwyn W; Jeffrey, Robert R

    2014-01-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was, 'in [patients with heparin resistance] is [treatment with FFP] superior [to antithrombin administration] in [achieving adequate anticoagulation to facilitate safe cardiopulmonary bypass]?' More than 29 papers were found using the reported search, of which six represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Antithrombin (AT) binds to heparin and increases the rate at which it binds to thrombin. The levels of antithrombin in the blood are an important aspect of the heparin dose-response curve. When the activated clotting time (ACT) fails to reach a target >480, this is commonly defined as heparin resistance (HR). Heparin resistance is usually treated with a combination of supplementary heparin, fresh frozen plasma (FFP) or antithrombin III concentrate. There is a paucity of evidence on the treatment of heparin resistance with FFP, with only five studies identified, including one retrospective study, one in vitro trial and three case reports. AT has been studied more extensively with multiple studies, including a crossover trial comparing AT to supplemental heparin and a multicentre, randomized, double blind, placebo-controlled trial. Antithrombin (AT) concentrate is a safe and efficient treatment for heparin resistance to elevate the activated clotting time (ACT). It avoids the risk of transfusion-related acute lung injury (TRALI), volume overload, intraoperative time delay and viral or vCJD transmission. Antithrombin concentrates are more expensive than fresh frozen plasma and may put patients at risk of heparin rebound in the early postoperative period. Patients treated with AT have a lower risk of further FFP transfusions during their stay in hospital. We conclude that the treatment of

  1. A capillary zone electrophoresis method to detect conformers and dimers of antithrombin in therapeutic preparations.

    Science.gov (United States)

    Marie, Anne-Lise; Tran, Nguyet Thuy; Saller, François; Abdou, Youmna Mohamed; Zeau, Pascal; Plantier, Jean-Luc; Urbain, Rémi; Borgel, Delphine; Taverna, Myriam

    2016-07-01

    Antithrombin (AT) is a human plasma glycoprotein that possesses anticoagulant and anti-inflammatory properties. However, the native (active) form of AT is unstable and undergoes conformational changes, leading to latent, cleaved, and heterodimeric forms. The presence of these alternative forms mostly inactive can highly impact the quality and therapeutic activity of pharmaceutical AT preparations. We developed a capillary zone electrophoresis method, based on a neutral polyethylene oxide-coated capillary and a buffer close to physiological conditions, enabling the separation of more than eight forms of AT. Several peaks were identified as native, latent, and heterodimeric forms. The CZE method was reproducible with intraday relative standard deviations less than 0.5 and 2% for migration times and peak areas, respectively. The method was applied to the comparison of AT preparations produced by five competitive pharmaceutical companies, and statistical tests were performed. Important differences in the proportion of each form were highlighted. In particular, one AT preparation was shown to contain a high quantity of heterodimer, and two preparations contained high quantities of latent form. In addition, one AT preparation exhibited additional forms, not yet identified. PMID:26989842

  2. Prevention, management and extent of adverse pregnancy outcomes in women with hereditary antithrombin deficiency.

    Science.gov (United States)

    Rogenhofer, Nina; Bohlmann, Michael K; Beuter-Winkler, Petra; Würfel, Wolfgang; Rank, Andreas; Thaler, Christian J; Toth, Bettina

    2014-03-01

    Antithrombin (AT) deficiency is a rare hereditary thrombophilia with a mean prevalence of 0.02 % in the general population, associated with a more than ten-fold increased risk of venous thromboembolism (VTE). Within this multicenter retrospective clinical analysis, female patients with inherited AT deficiency were evaluated concerning the type of inheritance and extent of AT deficiency, medical treatment during pregnancy and postpartally, VTE risk as well as maternal and neonatal outcome. Statistical analysis was performed with SPPS for Windows (19.0). A total of 18 pregnancies in 7 patients were evaluated, including 11 healthy newborns ≥37th gestational weeks (gw), one small for gestational age premature infant (25th gw), two late-pregnancy losses (21st and 28th gw) and four early miscarriages. Despite low molecular weight heparin (LMWH) administration, three VTE occurred during pregnancy and one postpartally. Several adverse pregnancy outcomes occurred including fetal and neonatal death, as well as severe maternal neurologic disorders occurred. Patients with substitution of AT during pregnancy in addition to LMWH showed the best maternal and neonatal outcome. Close monitoring with appropriate anticoagulant treatment including surveillance of AT levels might help to optimize maternal and fetal outcome in patients with hereditary AT deficiency.

  3. Fondaparinux bei Herz-Kreislauf-Erkrankungen: Ein neues Antithrombin mit herausragenden Eigenschaften

    Directory of Open Access Journals (Sweden)

    Huber K

    2008-01-01

    Full Text Available Fondaparinux, ein synthetisches Pentasaccharid, führt zu einer indirekten Hemmung des Gerinnungsfaktors Xa und behindert in der Folge die Bildung von Thrombin. Fondaparinux wurde als Vergleichssubstanz gegenüber unfraktioniertem (Standard- Heparin oder dem niedermolekularen Heparin Enoxaparin in der Prophylaxe oder Therapie von venösen Thrombosen getestet. Zuletzt wurde Fondaparinux auch bei Patienten mit akuten Koronarsyndromen (ACS untersucht: bei Patienten mit ACS ohne ST-Hebung (NSTE-ACS waren sowohl die Blutungsrate als auch die Kurz- und Langzeitmortalität im Fondaparinuxarm (2,5 mg/Tag s. c. signifikant geringer als in den Enoxaparin-behandelten Patienten (1 mg/kg KG 2×/Tag s. c. (OASIS-5-Studie. Bei Patienten mit akutem ST-Strecken-Hebungsinfarkt (STEMI war Fondaparinux in den Subgruppen der konservativ behandelten Patienten (ohne Reperfusion und der Patienten, die eine pharmakologische Reperfusion erhielten (Thrombolyse von Vorteil gegenüber Placebo oder unfraktioniertem Heparin. Hingegen zeigte sich bei Patienten mit STEMI, die einer Akut-PCI unterzogen wurden, eine starke Tendenz zugunsten von unfraktioniertem Heparin gegenüber Fondaparinux (OASIS-6-Studie. Daher wird Fondaparinux in den internationalen Richtlinien als das Antithrombin mit der günstigsten Risiko/Nutzen-Ratio bei NSTEMI aber auch bei STEMI-Patienten mit Ausnahme jener Patienten, die sich einer Akut-PCI unterziehen, empfohlen. Fondaparinux könnte schon in der nahen Zukunft die Heparine in diesen Indikationen weitgehend ersetzen.

  4. Recombination instability

    DEFF Research Database (Denmark)

    D'Angelo, N.

    1967-01-01

    A recombination instability is considered which may arise in a plasma if the temperature dependence of the volume recombination coefficient, alpha, is sufficiently strong. Two cases are analyzed: (a) a steady-state plasma produced in a neutral gas by X-rays or high energy electrons; and (b...

  5. Biological Variations of Lupus Anticoagulant, Antithrombin, Protein C, Protein S, and von Willebrand Factor Assays.

    Science.gov (United States)

    Shou, Weiling; Chen, Qian; Wu, Wei; Cui, Wei

    2016-02-01

    The results of lupus anticoagulant (LA), antithrombin (AT), protein C (PC), and protein S (PS) testing, and the values of von Willebrand factor antigen (VWF:Ag) are important in diagnosis and therapeutic monitoring of thrombosis and hemostasis diseases. Till now, no published study has focused on the biological variations in LA testing, and only a few studies have examined the biological variations of AT, PC, PS, and VWF:Ag. With the latest fully automated instruments and improved reagents, the analytical, within-subject, and between-subject biological variations were estimated for these five coagulant parameters in a cohort of 25 apparently healthy subjects. Blood specimens were collected at 8:00 am, 12:00 pm, and 4:00 pm on days 1, 3, and 5. The analytical biological variation (CV(A)) values of all the parameters were less than 3%. The within-subject biological variation (CV(W)) and between-subject biological variation (CV(G)) values of the LA normalized ratio were 4.64 and 6.83%, respectively. No significant differences were observed in the intraday and interday biological variations of LA tests, or in AT, PC, PS, and VWF:Ag values. Additionally, the utility of the conventional population-based reference intervals of the five coagulation parameters was evaluated by the index of individuality, and data on CV(W) and CV(A) were used to calculate the reference change value to identify the significance of changes in serial results from the same individual. PMID:26516946

  6. Antithrombin reduces reperfusion-induced hepatic metastasis of colon cancer cells

    Institute of Scientific and Technical Information of China (English)

    Masanao Kurata; Kenji Okajima; Toru Kawamoto; Mitsuhiro Uchiba; Nobuhiro Ohkohchi

    2006-01-01

    AIM: To examine whether antithrombin (AT) could prevent hepatic ischemia/reperfusion (I/R)-induced hepatic metastasis by inhibiting tumor necrosis factor (TNF)-α-induced expression of E-selectin in rats.METHODS: Hepatic I/R was induced in rats and mice by clamping the left branches of the portal vein and the hepatic artery. Cancer cells were injected intrasplenically.The number of metastatic nodules was counted on day 7after I/R. TNF-α and E-selectin mRNA in hepatic tissue,serum fibrinogen degradation products and hepatic tissue levels of 6-keto-PGF1α, a stable metabolite of PGI2,were measured.RESULTS: AT inhibited increases in hepatic metastasis of tumor cells and hepatic tissue mRNA levels of TNF-αand E-selectin in animals subjected to hepatic I/R.Argatroban, a thrombin inhibitor, did not suppress any of these changes. Both AT and argatroban inhibited I/R-induced coagulation abnormalities. I/R-induced increases of hepatic tissue levels of 6-keto-PGF1αwere significantly enhanced by AT. Pretreatment with indomethacin completely reversed the effects of AT.Administration of OP-2507, a stable PGI2 analog, showed effects similar to those of AT in this model. Hepatic metastasis in congenit.al AT-deficient mice subjected to hepatic I/R was significantly increased compared to that observed in wild-type mice. Administration of AT significantly reduced the number of hepatic metastases in congenital AT-deficient mice.CONCLUSION: AT might reduce I/R-induced hepatic metastasis of colon cancer cells by inhibiting TNF-α-induced expression of E-selectin through an increase in the endothelial production of PGI2. These findings also raise the possibility that AT might prevent hepatic metastasis of tumor cells if administered during the resection of liver tumors.

  7. Antithrombin up-regulates AMP-activated protein kinase signalling during myocardial ischaemia/reperfusion injury.

    Science.gov (United States)

    Ma, Yina; Wang, Jinli; Gao, Junjie; Yang, Hui; Wang, Yanqing; Manithody, Chandrashekhara; Li, Ji; Rezaie, Alireza R

    2015-02-01

    Antithrombin (AT) is a protein of the serpin superfamily involved in regulation of the proteolytic activity of the serine proteases of the coagulation system. AT is known to exhibit anti-inflammatory and cardioprotective properties when it binds to heparan sulfate proteoglycans (HSPGs) on vascular cells. AMP-activated protein kinase (AMPK) plays an important cardioprotective role during myocardial ischaemia and reperfusion (I/R). To determine whether the cardioprotective signaling function of AT is mediated through the AMPK pathway, we evaluated the cardioprotective activities of wild-type AT and its two derivatives, one having high affinity and the other no affinity for heparin, in an acute I/R injury model in C57BL/6J mice in which the left anterior descending coronary artery was occluded. The serpin derivatives were given 5 minutes before reperfusion. The results showed that AT-WT can activate AMPK in both in vivo and ex vivo conditions. Blocking AMPK activity abolished the cardioprotective function of AT against I/R injury. The AT derivative having high affinity for heparin was more effective in activating AMPK and in limiting infraction, but the derivative lacking affinity for heparin was inactive in eliciting AMPK-dependent cardioprotective activity. Activation of AMPK by AT inhibited the inflammatory c-Jun N-terminal protein kinase (JNK) pathway during I/R. Further studies revealed that the AMPK activity induced by AT also modulates cardiac substrate metabolism by increasing glucose oxidation but inhibiting fatty acid oxidation during I/R. These results suggest that AT binds to HSPGs on heart tissues to invoke a cardioprotective function by triggering cardiac AMPK activation, thereby attenuating JNK inflammatory signalling pathways and modulating substrate metabolism during I/R. PMID:25230600

  8. Deficiencies of proteins C, S and Antithrombin and factor V Leiden and the risk of ischemic strokes

    Science.gov (United States)

    Popa, C

    2010-01-01

    Although hypercoagulable states are most often associated with venous thromboses, arterial thromboses are reported in protein C, protein S, antithrombin deficient patients and in those with factor V Leiden, components of hereditary thrombophilia. Because these arterial thromboses (peripheral artery disease, myocardial infarction, and cerebral infarction) mostly affect young persons, aged below 45 years, it is important to test and treat these thrombophilic defects. Because the relation thrombophilia – arterial thromboses is still under debate, due to conflicting data, this article is a review of studies published in literature regarding the implication of the above–mentioned thrombophilic defects in cerebral infarcts. PMID:20945813

  9. On the specificity of heparin/heparan sulfate binding to proteins. Anion-binding sites on antithrombin and thrombin are fundamentally different.

    Directory of Open Access Journals (Sweden)

    Philip D Mosier

    Full Text Available BACKGROUND: The antithrombin-heparin/heparan sulfate (H/HS and thrombin-H/HS interactions are recognized as prototypic specific and non-specific glycosaminoglycan (GAG-protein interactions, respectively. The fundamental structural basis for the origin of specificity, or lack thereof, in these interactions remains unclear. The availability of multiple co-crystal structures facilitates a structural analysis that challenges the long-held belief that the GAG binding sites in antithrombin and thrombin are essentially similar with high solvent exposure and shallow surface characteristics. METHODOLOGY: Analyses of solvent accessibility and exposed surface areas, gyrational mobility, symmetry, cavity shape/size, conserved water molecules and crystallographic parameters were performed for 12 X-ray structures, which include 12 thrombin and 16 antithrombin chains. Novel calculations are described for gyrational mobility and prediction of water loci and conservation. RESULTS: The solvent accessibilities and gyrational mobilities of arginines and lysines in the binding sites of the two proteins reveal sharp contrasts. The distribution of positive charges shows considerable asymmetry in antithrombin, but substantial symmetry for thrombin. Cavity analyses suggest the presence of a reasonably sized bifurcated cavity in antithrombin that facilitates a firm 'hand-shake' with H/HS, but with thrombin, a weaker 'high-five'. Tightly bound water molecules were predicted to be localized in the pentasaccharide binding pocket of antithrombin, but absent in thrombin. Together, these differences in the binding sites explain the major H/HS recognition characteristics of the two prototypic proteins, thus affording an explanation of the specificity of binding. This provides a foundation for understanding specificity of interaction at an atomic level, which will greatly aid the design of natural or synthetic H/HS sequences that target proteins in a specific manner.

  10. Production of recombinant proteins in milk of transgenic and non-transgenic goats

    Directory of Open Access Journals (Sweden)

    Raylene Ramos Moura

    2011-10-01

    Full Text Available Among all the transgenic mammalians produced so far, goats have represented an excellent model of transgenesis when considering the factors such as the market demand for protein, volume of milk produced per lactation and reproductive rate. Various recombinant proteins have been obtained from the transgenic and non-transgenic goats, and among these, human antithrombin, produced by the transgenic goats, was the first recombinant protein of animal origin to be released as a drug for the clinical use in humans. This review reports the aspects inherent to the production of recombinant proteins in the goats, from the production of the animal bioreactors up to the expression of these proteins in their milk.

  11. The conformational activation of antithrombin. A 2.85-A structure of a fluorescein derivative reveals an electrostatic link between the hinge and heparin binding regions.

    Science.gov (United States)

    Huntington, J A; McCoy, A; Belzar, K J; Pei, X Y; Gettins, P G; Carrell, R W

    2000-05-19

    Antithrombin is unique among the serpins in that it circulates in a native conformation that is kinetically inactive toward its target proteinase, factor Xa. Activation occurs upon binding of a specific pentasaccharide sequence found in heparin that results in a rearrangement of the reactive center loop removing constraints on the active center P1 residue. We determined the crystal structure of an activated antithrombin variant, N135Q S380C-fluorescein (P14-fluorescein), in order to see how full activation is achieved in the absence of heparin and how the structural effects of the substitution in the hinge region are translated to the heparin binding region. The crystal structure resembles native antithrombin except in the hinge and heparin binding regions. The absence of global conformational change allows for identification of specific interactions, centered on Glu(381) (P13), that are responsible for maintenance of the solution equilibrium between the native and activated forms and establishes the existence of an electrostatic link between the hinge region and the heparin binding region. A revised model for the mechanism of the allosteric activation of antithrombin is proposed.

  12. Resolution of preoperative portal vein thrombosis after administration of antithrombin III in living donor liver transplantation: case report.

    Science.gov (United States)

    Imai, H; Egawa, H; Kajiwara, M; Nakajima, A; Ogura, Y; Hatano, E; Ueda, M; Kawaguchi, Y; Kaido, T; Takada, Y; Uemoto, S

    2009-11-01

    A 59-year-old man with hepatitis C virus-associated liver cirrhosis was transferred to our hospital to undergo living donor liver transplantation. Coagulation was impaired (prothrombin time [International Normalized Ratio], 3.27), and antithrombin III (AT-III) activity was 23% (normal, 87%-115%). Contrast-enhanced computed tomography scans revealed portal vein thrombosis (PVT) from the junction between the splenic and superior mesenteric vein to the porta hepatica; the portal vein was completely obstructed (PVT). To prevent further development of PVT, 1500 U of AT-III was administered for 3 days, elevating the AT-III activity to 50%. A contrast-enhanced computed tomography scan obtained 9 days after AT-III administration showed resolution of PVT. Living donor liver transplantation was safely performed without portal vein grafting. Thus, a low AT-III concentration may have an important role in the pathogenesis of PVT in patients with cirrhosis. PMID:19917415

  13. [Preparation and antithrombogenicity of oxidated low molecular weight heparin-antithrombin complex coated-polyvinyl chloride tubing].

    Science.gov (United States)

    Luo, Peng; Liu, Weiyong; Yang, Chun; Zhou, Hua; Cao, Ruijun; Yang, Jian

    2011-02-01

    Based on non-enzymatic protein glycated reaction, the sodium periodate-oxidated low molecular weight heparin-antithrombin covalent complex (SPLMWATH) was produced. By using polyethyleneimine-glutaraldehyde bonding technique, polyvinyl chloride (PVC) tubings were coated with SPLMWATH, heparin and low molecular weight heparin (LMWH). Spectrophotometry and dynamic clotting time experiment were used to determine the synthetic ratio of SPLMWATH, graft density, coating leaching ratio and to evaluate the antithrombogenicity of different coating on the PVC tubings. The results showed that the synthetic ratio of SPLMWATH was approximately 55%, and compared with heparin coating and LMWH coating, the graft density of SPLMWATH coating on the PVC tubing was smaller, but its coating stability and antithrombogenicity were significantly better than that of heparin coating and LMWH coating on the PVC tubings.

  14. Development of Methods for Measuring Protein C Inhibitor and Antithrombin: Use of Monoclonal Antibodies against the Reactive Center Loop-Inserted Forms of the Serpins

    OpenAIRE

    Kjellberg, Margareta

    2007-01-01

    Protein C inhibitor (PCI) and antithrombin (AT) are serine protease inhibitors (serpins) that are involved in the regulation of coagulation. Like other inhibitory serpins, PCI and AT adopt different structural conformations that are related to their functions. The cleaved, inactive form is a result of cleavage by a protease, and the latent form, which is also inactive, can arise due to a mutation in the serpin. Methods that quantify the different forms can be useful as diagnostic tools. The a...

  15. Purified radiolabeled antithrombin III metabolism in three families with hereditary AT III deficiency: application of a three-compartment model

    International Nuclear Information System (INIS)

    Purified human radioiodinated antithrombin III (125I-AT III) was used to study its metabolism in six members from three different families with a known hereditary AT III deficiency. Six healthy volunteers served as a control group. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and crossed immunoelectrophoresis (CIE) showed the purified AT III to be homogeneous. Amino acid analysis of the protein revealed a composition identical to a highly purified internal standard. The specific activity was 5.6 U/mg. Analysis of plasma radioactivity data was performed, using a three-compartment model. Neither plasma disappearance half-times nor fractional catabolic rate constants differed significantly between patients and control subjects. The mean absolute catabolic rate in the patient group was significantly lower than that of the control group at 2.57 +/- 0.44 and 4.46 +/- 0.80 mg/kg/day, respectively. In addition, the mean patient alpha 1-phase, flux ratio (k1,2 and k2,1) of the second compartment alpha 2-phase and influx (k3,1) of the third compartment were significantly reduced as compared with control values. It has been tentatively concluded that the observed reduction in the second compartment may be caused by a decrease in endothelial cell surface binding

  16. Circulating microparticles and the risk of thrombosis in inherited deficiencies of antithrombin, protein C and protein S.

    Science.gov (United States)

    Campello, Elena; Spiezia, Luca; Radu, Claudia M; Bulato, Cristiana; Gavasso, Sabrina; Tormene, Daniela; Woodhams, Barry; Dalla Valle, Fabio; Simioni, Paolo

    2016-01-01

    Many subjects carrying inherited thrombophilic defects will never experience venous thromboembolism (VTE) while other individuals developed recurrent VTE with no known additional risk factors. High levels of circulating microparticles (MP) have been associated with increased risk of VTE in patients with factor V Leiden and prothrombin G20210A mutation, suggesting a possible contribution of MP in the hypercoagulability of mild genetic thrombophilia. The role of MP as additional risk factor of VTE in carriers of natural clotting inhibitors defects (severe thrombophilia) has never been assessed. Plasma levels of annexin V-MP, endothelial-derived MP (EMP), platelet-derived MP (PMP), tissue factor-bearing MP (TF+) and the MP procoagulant activity (PPL) were measured in 132 carriers of natural anticoagulant deficiencies (25 antithrombin, 63 protein C and 64 protein S defect) and in 132 age and gender-matched healthy controls. Carriers of natural anticoagulant deficiencies, overall and separately considered, presented with higher median levels of annexin V-MP, EMP, PMP, TF+MP and PPL activity than healthy controls (pEMP and PMP had an adjusted OR for VTE of 3.36 (95% CI, 1.59 to 7.11), 9.26 (95% CI, 3.55 to 24.1) and 2.72 (95%CI, 1.16 to 6.38), respectively. Elevated levels of circulating MP can play a role in carriers of mild and severe inherited thrombophilia. The clinical implications of this association remain to be defined. PMID:26354831

  17. [Study on antiplatelet and antithrombin activitives and effective components variation of Puhuang-Wulingzhi before and after compatibility].

    Science.gov (United States)

    Su, Shu-lan; Xue, Ping; Ouyang, Zhen; Zhou, Wei; Duan, Jin-ao

    2015-08-01

    The changes of bioactive constituents were analyzed for Puhuang-Wulingzhi before and after compatibility and the antiplatelet and antithrombin activitives were evaluated in order to elucidate the scientific and reasonable of Puhuang-Wulingzhi compatibility. UPLC-QTOF-MA-Markerlynx, principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis were used for data analysis and tracking changes of chemical composition during the decocting process. In vitro platelet aggregation induced by ADP, thrombin time(TT) and prothrombin time (PT) were investigated for Puhuang-Wulingzhi before and after compatibility. The results showed that significant differences were found between the mixed decoction and codecoction of Wulingzhi and Puhuang. Five compounds changed obviously were identified as typhaneoside, naringenin, isorhamnetin-3-O-ruinoside, quercetin-3-O-neohesperidoside, kaempferol-3-O-neohesperidoside. The codecoction, comparing with the single decoction, was more significant in antiplatelet aggregation and could prolong thrombin time. In the same crude drug dose, the thrombin time (TT) elongation were greater. These data could provide references for elucidation of bioactive components for this herb pair. PMID:26790290

  18. Recombinant Technology and Probiotics

    Directory of Open Access Journals (Sweden)

    Icy D’Silva

    2011-09-01

    Full Text Available Recombinant technology has led the way to monumental advances in the development of useful molecules, including the development of safe probiotics. The development of novel approaches using recombinant technology and probiotics that allow accurate targeting of therapeutics to the mucosa is an interesting area of research. The creation and use of recombinant probiotics expressing recombinantovalbumin, recombinant ovalbumin mutants and yet-to-be-designed recombinant hypo/non-allergenic molecules offer the opportunity to further investigate their effects for food, nutrition, environment andhealth. This review highlights advances in native probiotics and recombinant probiotics expressing native and recombinant molecules for food, nutrition, environment and health.

  19. Comparison of biological activities of human antithrombins with high-mannose or complex-type nonfucosylated N-linked oligosaccharides.

    Science.gov (United States)

    Yamada, Tsuyoshi; Kanda, Yutaka; Takayama, Makoto; Hashimoto, Akitoshi; Sugihara, Tsutomu; Satoh-Kubota, Ai; Suzuki-Takanami, Eri; Yano, Keiichi; Iida, Shigeru; Satoh, Mitsuo

    2016-05-01

    The structure of the N-linked oligosaccharides attached to antithrombin (AT) has been shown to affect its anticoagulant activity and pharmacokinetics. Human AT has biantennary complex-type oligosaccharides with the unique feature of lacking a core fucose, which affects its biological activities by changing its heparin-binding affinity. In human plasma, AT circulates as a mixture of the α-form bearing four oligosaccharides and the β-form lacking an oligosaccharide at Asn135. However, it remains unclear how the immature high-mannose-type oligosaccharides produced by mammalian cells affect biological activities of AT. Here, we succeeded in directly comparing the activities between the high-mannose and complex types. Interestingly, although there were no substantial differences in thrombin inhibitory activity, the high-mannose type showed higher heparin-binding affinity. The anticoagulant activities were increased by heparin and correlated with the heparin-binding affinity, resulting in the strongest anticoagulant activity being displayed in the β-form with the high-mannose type. In pharmacokinetic profiling, the high-mannose type showed a much shorter plasma half-life than the complex type. The β-form was found to have a prolonged plasma half-life compared with the α-form for the high-mannose type; conversely, the α-form showed a longer half-life than the β-form for the complex-type. The present study highlights that AT physiological activities are strictly controlled not only by a core fucose at the reducing end but also by the high-mannose-type structures at the nonreducing end. The β-form with the immature high-mannose type appears to function as a more potent anticoagulant than the AT typically found in human plasma, once it emerges in the blood. PMID:26747427

  20. Engineering D-helix of antithrombin in alpha-1-proteinase inhibitor confers antiinflammatory properties on the chimeric serpin.

    Science.gov (United States)

    Yang, L; Dinarvand, P; Qureshi, S H; Rezaie, A R

    2014-07-01

    Antithrombin (AT) is a heparin-binding serpin in plasma which regulates the proteolytic activity of procoagulant proteases of the clotting cascade. In addition to being an anticoagulant, AT also exhibits antiinflammatory activities when it binds to cell surface heparan sulfate proteoglycans (HSPGs) on the endothelium via its basic residues of D-helix to elicit intracellular signalling responses. By contrast to AT, α1-proteinase inhibitor (α1-PI) is a non-heparin-binding serpin that exhibits very slow reactivity with coagulation proteases and possesses no HSPG-dependent antiinflammatory properties. To determine whether the antiinflammatory signaling specificity of AT can be transferred to α1-PI, we replaced the D-helix of human α1-PI with the corresponding sequence of human AT and expressed the chimeric serpin α1-PI/D-helix) in a bacterial expression system. High molecular weight heparin bound to α1-PI/D-helix and accelerated the inhibition of thrombin by the serpin mutant by a template mechanism reminiscent of the cofactor effect of heparin on inhibition of thrombin by AT. Like AT, α1-PI/D-helix exhibited antiinflammatory properties in both cellular and animal models. Thus, α1-PI/D-helix inhibited the barrier-disruptive effect of proinflammatory cytokines and inhibited the activation of nuclear factor-κB transcription factor in lipopolysaccharide-stimulated endothelial cells by a concentration-dependent manner. Furthermore, the chimeric serpin reduced lipopolysaccharide-mediated lethality, elicited a vascular protective effect and inhibited infiltration of activated leukocytes to the peritoneal cavity of mice in an HMGB1-mediated inflammatory model. These results suggest that grafting the D-helix of AT to α1-PI confers antiinflammatory properties on the serpin and that the chimeric serpin may have therapeutic utility for treating inflammatory disorders. PMID:24522239

  1. Impact of antithrombin Ⅲ on hepatic and intestinal microcirculation in experimental liver cirrhosis and bowel inflammation: An in vivo analysis

    Institute of Scientific and Technical Information of China (English)

    Sasa-Marcel Maksan; Zilfi (U)lger; Martha Maria Gebhard; Jan Schmidt

    2005-01-01

    AIM: To analyze the hepatic and intestinal microcirculation in an animal model of liver cirrhosis and inflammatory bowel disease (IBD) and to characterize the anti-inflammatory action of antithrombin Ⅲ (ATⅢ) on leukocyte kinetics and liver damage.METHODS: Hepatic and intestinal microcirculation was investigated by intravital videomicroscopy. Standardized models of experimental chronic liver cirrhosis and bowel inflammation were employed. Animals were divided into four groups (n = 6/group): controls, animals with cirrhosis,animals with cirrhosis and IBD, animals with cirrhosis and IBD treated with ATⅢ.RESULTS: Cirrhosis facilitated leukocyte rolling and sticking in hepatic sinusoids (1.91±0.28 sticker/μm vs0.5±0.5 sticker/μm in controls, P<0.05). The effect enhanced in animals with cirrhosis and IBD (5.4±1.65sticker/μm), but reversed agter ATⅢ application (3.97±1.04sticker/μm, P<0.05). Mucosal blood flow showed no differences in cirrhotic animals and controls (5.3±0.31nL/min vs5.4±0.25 nL/min) and was attenuated in animals with cirrhosis and IBD significantly (3.49±0.6 nL/min). This effect was normalized in the treatment group (5.13±0.4nL/min, P<0.05). Enzyme values rose during development of cirrhosis and bowel inflammation, and reduced after ATⅢ application (P<0.05).CONCLUSION: Liver cirrhosis in the presence of IBD leads to a significant reduction in mucosal blood flow and an increase in hepatic leukocyte adherence with consecutive liver injury, which can be prevented by administration of ATⅢ.

  2. Analysis of blood coagulation in mice: pre-analytical conditions and evaluation of a home-made assay for thrombin-antithrombin complexes

    Directory of Open Access Journals (Sweden)

    Meijers Joost CM

    2005-08-01

    Full Text Available Abstract Background The use of mouse models for the study of thrombotic disorders has gained increasing importance. Methods for measurement of coagulation activation in mice are, however, scarce. The primary aim of this study was to develop a specific mouse thrombin-antithrombin (TAT ELISA for measurement of coagulation activation and to compare it with two commercially available assays for human TAT complexes. In addition, we aimed to improve methods for mouse plasma anticoagulation and preparation. Methods and results First, for the measurement of TAT-complexes in plasma a mouse specific TAT-ELISA was developed using rabbit polyclonal antibodies raised against mouse thrombin and rat antithrombin, respectively. This ELISA detected an increase in TAT levels in a mouse model of endotoxemia. Two commercial human TAT ELISAs appeared to be less specific for mouse thrombin-rat antithrombin complexes. Second, to prevent clotting of mouse blood sodium citrate was either mixed with blood during collection in a syringe or was injected intravenously immediately prior to blood collection. Intravenous sodium citrate completely inhibited blood coagulation resulting in plasma with consistently low TAT levels. Sodium citrate mixed with blood during collection resulted in increased TAT levels in 4 out of 16 plasma samples. Third, heparinase was added to plasma samples after in vivo injection of different heparin doses to test its neutralizing effect. Heparinase neutralized up to a 20 U of heparin/mouse and resulted in accurate APTT and factor VIII determinations. Conclusion These procedures and reagents for plasma preparation and coagulation testing will improve studies on thrombotic disorders in mice.

  3. 新鲜冰冻血浆与普通冰冻血浆抗凝血酶Ⅲ活性研究%Study on antithrombin III activity between fresh frozen plasma and common frozen plasma

    Institute of Scientific and Technical Information of China (English)

    解学龙; 欧阳龙; 夏耀宗; 张涛

    2015-01-01

    Objective To investigate the antithrombin III activity difference in fresh frozen plasma and common frozen plasma. Methods Determines antithrombin III activity between 30 examples to fresh frozen plasma and 30 examples common frozen plasma by Useing the Shanghai sun antithrombin III reagent box in the German BE Compact-X Full automatic blood coagulation analyzer.Results Antithrombin III activity of 30 cases fresh frozen plasma is 110+8.6 % and antithrombin III activity of 30 cases normal frozen plasma is 90+8.5%.Conclusions Antithrombin III activity of fresh frozen plasma is significantly higher than normal frozen plasma.%目的:探讨抗凝血酶Ⅲ在新鲜冰冻血浆和普通冰冻血浆活性差异。方法:采用上海太阳抗凝血酶Ⅲ试剂盒在德国BE Compact-X全自动血凝仪测定30例新鲜冰冻血浆和30例普通冰冻血浆的凝血酶Ⅲ活性。结果:30例新鲜冰冻血浆和30例普通冰冻血浆的凝血酶Ⅲ活性分别是110+8.6%和90+8.5%。结论:新鲜冰冻血浆抗凝血酶Ⅲ活性明显高于普通冰冻血浆的抗凝血酶Ⅲ活性。

  4. Recombinant DNA in Medicine

    OpenAIRE

    Cederbaum, Stephen D.; Fareed, George C.; Lovett, Michael A.; Shapiro, Larry J.

    1984-01-01

    Studies in bacteria and bacterial viruses have led to methods to manipulate and recombine DNA in unique and reproducible ways and to amplify these recombined molecules millions of times. Once properly identified, the recombinant DNA molecules can be used in various ways useful in medicine and human biology. There are many applications for recombinant DNA technology. Cloned complementary DNA has been used to produce various human proteins in microorganisms. Insulin and growth hormone have been...

  5. Improving baculovirus recombination

    OpenAIRE

    Zhao, Yuguang; Chapman, David A. G.; Jones, Ian M.

    2003-01-01

    Recombinant baculoviruses have established themselves as a favoured technology for the high-level expression of recombinant proteins. The construction of recombinant viruses, however, is a time consuming step that restricts consideration of the technology for high throughput developments. Here we use a targeted gene knockout technology to inactivate an essential viral gene that lies adjacent to the locus used for recombination. Viral DNA prepared from the knockout fails to initiate an infecti...

  6. Photoionization and Recombination

    Science.gov (United States)

    Nahar, Sultana N.

    2000-01-01

    Theoretically self-consistent calculations for photoionization and (e + ion) recombination are described. The same eigenfunction expansion for the ion is employed in coupled channel calculations for both processes, thus ensuring consistency between cross sections and rates. The theoretical treatment of (e + ion) recombination subsumes both the non-resonant recombination ("radiative recombination"), and the resonant recombination ("di-electronic recombination") processes in a unified scheme. In addition to the total, unified recombination rates, level-specific recombination rates and photoionization cross sections are obtained for a large number of atomic levels. Both relativistic Breit-Pauli, and non-relativistic LS coupling, calculations are carried out in the close coupling approximation using the R-matrix method. Although the calculations are computationally intensive, they yield nearly all photoionization and recombination parameters needed for astrophysical photoionization models with higher precision than hitherto possible, estimated at about 10-20% from comparison with experimentally available data (including experimentally derived DR rates). Results are electronically available for over 40 atoms and ions. Photoionization and recombination of He-, and Li-like C and Fe are described for X-ray modeling. The unified method yields total and complete (e+ion) recombination rate coefficients, that can not otherwise be obtained theoretically or experimentally.

  7. Recombineering Homologous Recombination Constructs in Drosophila

    OpenAIRE

    Carreira-Rosario, Arnaldo; Scoggin, Shane; Shalaby, Nevine A.; Williams, Nathan David; Hiesinger, P. Robin; Buszczak, Michael

    2013-01-01

    The continued development of techniques for fast, large-scale manipulation of endogenous gene loci will broaden the use of Drosophila melanogaster as a genetic model organism for human-disease related research. Recent years have seen technical advancements like homologous recombination and recombineering. However, generating unequivocal null mutations or tagging endogenous proteins remains a substantial effort for most genes. Here, we describe and demonstrate techniques for using recombineeri...

  8. A prospective cohort study on the absolute risks of venous thromboembolism and predictive value of screening asymptomatic relatives of patients with hereditary deficiencies of protein S, protein C or antithrombin

    NARCIS (Netherlands)

    Mahmoodi, B. K.; Brouwer, J-L P.; Ten Kate, M. K.; Lijfering, W. M.; Veeger, N. J. G. M.; Mulder, A. B.; Kluin-Nelemans, H. C.; van der Meer, J.

    2010-01-01

    Background: Absolute risks of venous thromboembolism (VTE) in protein S-, protein C-, or antithrombin-deficient subjects are mainly based on retrospective data. Screening asymptomatic relatives of these patients is disputed, though studies addressing this issue have yet to be conducted. Methods: We

  9. A prospective cohort study on the absolute risks of venous thromboembolism and predictive value of screening asymptomatic relatives of patients with hereditary deficiencies of protein S, protein C or antithrombin.

    NARCIS (Netherlands)

    Mahmoodi, B.K.; Brouwer, J.L.P.; Kate, M.K. Ten; Lijfering, W.M.; Veeger, N.J.; Mulder, A.B.; Kluin-Nelemans, H.C.; Meer, J. van der

    2010-01-01

    BACKGROUND: Absolute risks of venous thromboembolism (VTE) in protein S-, protein C-, or antithrombin-deficient subjects are mainly based on retrospective data. Screening asymptomatic relatives of these patients is disputed, though studies addressing this issue have yet to be conducted. METHODS: We

  10. Effect of NaC1 on inactivation of bovine thrombin by antithrombin III in the presence of low affinity-heparin or dextran sulfate.

    Science.gov (United States)

    Oshima, G; Nagasawa, K

    1986-02-01

    Heparin with low affinity (LA-heparin) to antithrombin III (AT III) enhanced the rate of inactivation of thrombin by AT III. The enhancement of the rate was saturable with AT III and was proportional to the LA-heparin concentration. Although the rate-enhancement in the presence of LA-heparin decreased with increase in NaC1 concentration, it was comparable with that in the presence of high affinity-heparin (HA-heparin) in the absence of NaC1. Inactivation of thrombin by AT III in the presence of dextran sulfate (DS) was also sensitive to NaC1 concentration. These findings indicate that free AT III is favorable for binding to the complexes of thrombin and highly sulfated polysaccharides having low affinities to AT III in the absence of NaC1.

  11. Human recombinant interleukin-1 beta- and tumor necrosis factor alpha-mediated suppression of heparin-like compounds on cultured porcine aortic endothelial cells

    International Nuclear Information System (INIS)

    Cytokines are known to tip the balance of the coagulant-anticoagulant molecules on the endothelial cell surface toward intravascular coagulation. Their effects on endothelial cell surface-associated heparin-like compounds have not been examined yet. Incorporation of [35S]sulfate into heparan sulfate on cultured porcine aortic endothelial cells was suppressed by human recombinant interleukin-1 beta (rIL-1 beta) or tumor necrosis factor alpha (rTNF alpha) in a dose- and time-dependent manner with little effect on cell number, protein content, and [3H]leucine incorporation of cells. Maximal inhibition was achieved by incubation of cells with 100 ng/ml of rIL-1 beta or 5 ng/ml of rTNF alpha for 12-24 hours, resulting in a reduction of the synthesis of heparan sulfate on the cell surface by approximately 50%. The dose dependency was consistent with that seen in the stimulation of endothelial cell procoagulant activity by each cytokine. The suppression of heparan sulfate synthesis was sustained for at least 48 hours after pretreatment of cells with cytokines and was unchanged after the addition of indomethacin or polymyxin B. The rate of degradation of prelabeled 35S-heparan sulfate on the cell surface was not altered by cytokine treatments. Neither the size, the net negative charge, nor the proportion of the molecule with high affinity for antithrombin III of endothelial cell heparan sulfate was changed by cytokines. Furthermore, specific binding of 125I-labeled antithrombin III to the endothelial cell surface was reduced to 40-60% of control by cytokines. In parallel with reduction in binding, antithrombin III cofactor activity was partially diminished in cytokine-treated endothelial cells. Thus, cytokine-mediated suppression of heparin-like substance on endothelial cells appears to be another cytokine-inducible endothelial effects affecting coagulation

  12. A recombinant wheat serpin with inhibitory activity

    DEFF Research Database (Denmark)

    Rasmussen, Søren K; Dahl, Søren Weis; Nørgård, Anette;

    1996-01-01

    to the subfamily of protein Z-type serpins and the amino acid sequence is 70%, identical with the barley serpins BSZ4 and BSZx and 27-33% identical with human serpins such as alpha(1)-proteinase inhibitor, antithrombin III, and plasminogen activator inhibitor. The cDNA was subcloned in the pET3d expression vector...

  13. Recombinant methods and materials

    Energy Technology Data Exchange (ETDEWEB)

    Roizman, B.; Post, L.E.

    1988-09-06

    This patent describes a method for stably effecting the insertion or deletion of a selected DNA sequence at a specific site in a viral genome. The method consists of: (1) isolating from the genome a linear DNA fragment comprising both (a) the specific site determined for insertion or deletion of selected DNA sequence and (b) flanking DNA sequences normally preceding and following the site; (2) preparing first and second altered genome fragments from the fragment isolated in step (1). (a) the first altered fragment comprising the fragment comprising a thymidine kinase gene in a position intermediate the ends of the fragment, and (b) the second altered fragment comprising the fragment having the selected DNA sequence inserted therein or deleted therefrom; (3) contacting the genome with the first altered fragment under conditions permitting recombination at sites of DNA sequence homology, selecting for a recombinant genome comprising the thymidine kinase gene, and isolating the recombinant genome; and (4) contacting the recombinant genome isolated in step (3) with the second altered fragment under conditions permitting recombination at sites of DNA sequence homology, selecting for a recombinant genome lacking the thymidine kinase gene, and isolating the recombinant genome product.

  14. Expression of Recombinant Antibodies

    OpenAIRE

    Frenzel, André; Hust, Michael; Schirrmann, Thomas

    2013-01-01

    Recombinant antibodies are highly specific detection probes in research, diagnostics, and have emerged over the last two decades as the fastest growing class of therapeutic proteins. Antibody generation has been dramatically accelerated by in vitro selection systems, particularly phage display. An increasing variety of recombinant production systems have been developed, ranging from Gram-negative and positive bacteria, yeasts and filamentous fungi, insect cell lines, mammalian cells to transg...

  15. Regulation of Meiotic Recombination

    Energy Technology Data Exchange (ETDEWEB)

    Gregory p. Copenhaver

    2011-11-09

    Meiotic recombination results in the heritable rearrangement of DNA, primarily through reciprocal exchange between homologous chromosome or gene conversion. In plants these events are critical for ensuring proper chromosome segregation, facilitating DNA repair and providing a basis for genetic diversity. Understanding this fundamental biological mechanism will directly facilitate trait mapping, conventional plant breeding, and development of genetic engineering techniques that will help support the responsible production and conversion of renewable resources for fuels, chemicals, and the conservation of energy (1-3). Substantial progress has been made in understanding the basal recombination machinery, much of which is conserved in organisms as diverse as yeast, plants and mammals (4, 5). Significantly less is known about the factors that regulate how often and where that basal machinery acts on higher eukaryotic chromosomes. One important mechanism for regulating the frequency and distribution of meiotic recombination is crossover interference - or the ability of one recombination event to influence nearby events. The MUS81 gene is thought to play an important role in regulating the influence of interference on crossing over. The immediate goals of this project are to use reverse genetics to identify mutants in two putative MUS81 homologs in the model plant Arabidopsis thaliana, characterize those mutants and initiate a novel forward genetic screen for additional regulators of meiotic recombination. The long-term goal of the project is to understand how meiotic recombination is regulated in higher eukaryotes with an emphasis on the molecular basis of crossover interference. The ability to monitor recombination in all four meiotic products (tetrad analysis) has been a powerful tool in the arsenal of yeast geneticists. Previously, the qrt mutant of Arabidopsis, which causes the four pollen products of male meiosis to remain attached, was developed as a facile system

  16. Concomitant homozygosity for the prothrombin gene variant with mild deficiency of antithrombin III in a patient with multiple hepatic infarctions: a case report

    Directory of Open Access Journals (Sweden)

    Macheta M

    2010-04-01

    Full Text Available Abstract Introduction Hereditary causes of visceral thrombosis or thrombosis should be sought among young patients. We present a case of a young man presenting with multiple hepatic infarctions resulting in portal hypertension due to homozygosity of the prothrombin gene mutation not previously described in literature. Case presentation A 42-year-old Caucasian man with a previous history of idiopathic deep vein thrombosis 11 years earlier presented with vague abdominal pains and mildly abnormal liver function tests. An ultrasound and computed tomography scan showed evidence of hepatic infarction and portal hypertension (splenic varices. A thrombophilia screen confirmed a homozygous mutation for the prothrombin gene mutation, with mildly reduced levels of anti-thrombin III (AT III. Subsequent testing of his father and brother revealed heterozygosity for the same gene mutation. Conclusion Hepatic infarction is unusual due to the rich dual arterial and venous blood supply to the liver. In the absence of an arterial or haemodynamic insult causing hepatic infarction, a thrombophilia should be considered. To our knowledge, this is the first reported case of a hepatic infarction due to homozygosity of the prothrombin gene mutation. It is unclear whether homozygotes have a higher risk of thrombosis than heterozygotes. In someone presenting with a first thrombosis with this mutation, the case for life-long anticoagulation is unclear, but it may be necessary to prevent a second and more severe second thrombotic event, as occurred in this case.

  17. 抗凝血酶-Ⅲ抗炎机制的研究进展%Advancement of anti-inflammatory mechanism of antithrombin-Ⅲ

    Institute of Scientific and Technical Information of China (English)

    孙辉明; 施毅

    2011-01-01

    Antithrombin-Ⅲ (AT-Ⅲ ),a physiological serine protease inhibitor,plays a critical role in the regulation of the coagulation cascade in human being.In addition to regulatory role in the coagulation system,AT-Ⅲ exerts a strong anti-inflammatory activity.This paper reviews the advancement of mechanism of AT-Ⅲ anti-inflammatory property in recent years.%抗凝血酶-Ⅲ是人体内最霞要的天然抗凝物质,其抗凝作用占体内总抗凝作用的50%~70%.近年来研究发现,抗凝血酶Ⅲ除了具有较强的抗凝作用外,还有另一种重要的分子生物学特性,即强大的抗炎作用.本文主要对近年来抗凝血酶Ⅲ抗炎机制的研究进展进行综述.

  18. Recombinant Helicobacter pylori catalase

    Institute of Scientific and Technical Information of China (English)

    Yang Bai; Ya-Li Zhang; Jian-Feng Jin; Ji-De Wang; Zhao-Shan Zhang

    2003-01-01

    AIM: To construct a recombinant strain which highly expresses catalase of Helicobacter pylori(H.pylori) and assay the activity of H. pylori catalase.METHODS: The catalase DNA was amplified from H. pylori chromosomal DNA with PCR techniques and inserted into the prokaryotie expression vector pET-22b (+), and then was transformed into the BL21 (DE3) E. coli strain which expressed catalase recombinant protein. The activity of H.pylori catalase was assayed by the Beers & Sizers.RESULTS: DNA sequence analysis showed that the sequence of catalase DNA was the same as GenBank's research. The catalase recombinant protein amounted to 24.4 % of the total bacterial protein after induced with IPTG for 3 hours at 37 ℃ and the activity of H. pylori catalase was high in the BL21 (DE3) E. coli strain.CONCLUSION: A clone expressing high activity H. pylori catalase is obtained, laying a good foundation for further studies.

  19. Recombination in ionized gases

    International Nuclear Information System (INIS)

    In this paper it is shown how capture-stabilized methodology (both macroscopic and microscopic) can provide a generic basis for a unified treatment of all of the above recombination mechanisms. A new semiclassical theory of dissociative recombination is also presented in an effort to gain further insight into the physics not included in the first-order treatment and difficult to extract from numerical quantal treatments based on configuration mixing and on multichannel quantum defect theory. A simple analytical expression more accurate than the standard first-order result is obtained for the cross section σ and rate coefficient α. (author)

  20. Recombinant DNA for Teachers.

    Science.gov (United States)

    Duvall, James G., III

    1992-01-01

    A science teacher describes his experience at a workshop to learn to teach the Cold Spring Harbor DNA Science Laboratory Protocols. These protocols lead students through processes for taking E. coli cells and transforming them into a new antibiotic resistant strain. The workshop featured discussions of the role of DNA recombinant technology in…

  1. Recombineering Pseudomonas syringae

    Science.gov (United States)

    Here we report the identification of functions that promote genomic recombination of linear DNA introduced into Pseudomonas cells by electroporation. The genes encoding these functions were identified in Pseudomonas syringae pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecE...

  2. High prevalence of protein C, protein S, antithrombin deficiency, and Factor V Leiden mutation as a cause of hereditary thrombophilia in patients of venous thromboembolism and cerebrovascular accident

    Science.gov (United States)

    Ali, Nadir; Ayyub, Muhammad; Khan, Saleem Ahmed

    2014-01-01

    Objectives: To determine the frequency of Protein C, Protein S (PC & PS), antithrombin deficiency (AT III) and Factor V Leiden mutation (FVL) as a cause of thrombophilia in the patients with venous thromboembolism (VTE) and cerebrovascular accident (CVA). Methods: It was an observational study conducted at Department of Haematology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan. All patients referred for thrombophilia screening from July 2009 to June 2012 were screened. Patients with evidence of VTE or CVA were screened for PC & PS, AT III deficiency, and FVL. Results: Total 404 patients of age between 1-71 years mean 33 ± 14 with male to female ratio of 2.4:1 had evidence of thrombophilia. Two hundred eighteen (54%) patients presented with CVA, 116 (29%) with deep vein thrombosis (DVT), 42 (10.5%) with pulmonary embolism (PE), and 28 (7.5%) with portal or mesenteric vein thrombosis (PV). Protein C & S deficiency was detected in 35/404 (8.7%), ATIII in 9/404 (2%), and FVL in 25/173 patients (14.5%). The findings were suggestive of a significant association of FVL mutation for developing DVT (OR=11.0, 95% C I 4.6-26.3), CVA (OR=5.7, 95% C I 2.1-15.1), and PV (OR=5.4, 95% C I 1.3-21.9). PC & PS deficiency was a significant risk factor for developing PE (OR=3, 95% C I 0.8-11.4). Conclusion: FVL mutation and Protein C & S are the leading causes of thrombophilia with strong association of Factor V Leiden mutation as risk for developing DVT. PMID:25674132

  3. AECL passive autocatalytic recombiners

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, L.B.; Marcinkowska, K. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2012-03-15

    Atomic Energy of Canada Limited's (AECL) Passive Autocatalytic Recombiner (PAR) is a passive device used for hydrogen mitigation under post-accident conditions in nuclear reactor containment. The PAR employs a proprietary AECL catalyst which promotes the exothermal reaction between hydrogen and oxygen to form water vapour. The heat of reaction combined with the PAR geometry establishes a convective flow through the recombiner, where ambient hydrogen-rich gas enters the PAR inlet and hot, humid, hydrogen-depleted gas exits the outlet. AECL's PAR has been extensively qualified for CANDU and light water reactors (LWRs), and has been supplied to France, Finland, Ukraine, South Korea and is currently being deployed in Canadian nuclear power plants. (author)

  4. AECL passive autocatalytic recombiners

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, L.B.; Marcinkowska, K. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2011-07-01

    Atomic Energy of Canada Limited's (AECL) Passive Autocatalytic Recombiner (PAR) is a passive device used for hydrogen mitigation under post-accident conditions in nuclear reactor containment. The PAR employs a proprietary AECL catalyst which promotes the exothermal reaction between hydrogen and oxygen to form water vapour. The heat of reaction combined with the PAR geometry establishes a convective flow through the recombiner, where ambient hydrogen-rich gas enters the PAR inlet and hot, humid, hydrogen-depleted gas exits the outlet. AECL's PAR has been extensively qualified for CANDU and light water reactors (LWRs), and has been supplied to France, Finland, Ukraine, South Korea and is currently being deployed in Canadian nuclear power plants. (author)

  5. RECOMBINANT INFLUENZA VACCINES

    OpenAIRE

    Sedova, E.; Shcherbinin, D.; Migunov, A.; Smirnov, Iu; Logunov, D.; Shmarov, M.; Tsybalova, L.; Naroditskiĭ, B.; O. Kiselev; Gintsburg, A.

    2012-01-01

    This review covers the problems encountered in the construction and production of new recombinant influenza vaccines. New approaches to the development of influenza vaccines are investigated; they include reverse genetics methods, production of virus-like particles, and DNA- and viral vector-based vaccines. Such approaches as the delivery of foreign genes by DNA- and viral vector-based vaccines can preserve the native structure of antigens. Adenoviral vectors are a promising gene-delivery pla...

  6. Soluble recombinant influenza vaccines.

    OpenAIRE

    Fiers, W; Neirynck, S; Deroo, T; Saelens, X; Jou, W M

    2001-01-01

    Soluble, recombinant forms of influenza A virus haemagglutinin and neuraminidase have been produced in cells of lower eukaryotes, and shown in a mouse model to induce complete protective immunity against a lethal virus challenge. Soluble neuraminidase, produced in a baculovirus system, consisted of tetramers, dimers and monomers. Only the tetramers were enzymatically active. The immunogenicity decreased very considerably in the order tetra > di > mono. Therefore, we fused the head part of the...

  7. PEGylation of Hirudin and Analysis of Its Antithrombin Activity in vitro%水蛭素聚乙二醇化及其体外抗凝活力分析

    Institute of Scientific and Technical Information of China (English)

    秦海娜; 修志龙; 张代佳; 包永明; 李晓晖; 韩国柱

    2007-01-01

    Hirudin is the most anticoagulant drug found in nature, but its short serum half-life significantly inhibits its clinical application. The PEGylation of hirudin, the most promising anticoagulant drug, was performed in this paper. The optimal reaction conditions for PEGylated hirudin were investigated. When the PEGylation reaction was conducted under 4℃ after 10h, in the borate buffer at pH 8.5, with the molar ratio 250: 1 of PEG to hirudin, a higher modification extent was achieved. Finally, the bioactivity of PEGylated hirudin was measured in vitro.Compared with unmodified hirudin, 26% of anti-thrombin activity was retained.

  8. Characterization of IXINITY® (Trenonacog Alfa, a Recombinant Factor IX with Primary Sequence Corresponding to the Threonine-148 Polymorph

    Directory of Open Access Journals (Sweden)

    Dougald M. Monroe

    2016-01-01

    Full Text Available The goal of these studies was to extensively characterize the first recombinant FIX therapeutic corresponding to the threonine-148 (Thr-148 polymorph, IXINITY (trenonacog alfa [coagulation factor IX (recombinant]. Gel electrophoresis, circular dichroism, and gel filtration were used to determine purity and confirm structure. Chromatographic and mass spectrometry techniques were used to identify and quantify posttranslational modifications. Activity was assessed as the ability to activate factor X (FX both with and without factor VIIIa (FVIIIa and in a standard clotting assay. All results were consistent across multiple lots. Trenonacog alfa migrated as a single band on Coomassie-stained gels; activity assays were normal and showed 97%  γ-carboxylation and underwent the appropriate structural change upon binding calcium ions. Trenonacog alfa was activated normally with factor XIa (FXIa; once activated it bound to FVIIIa and FXa. When activated to FIXa, it was inhibited efficiently by antithrombin. Glycosylation patterns were similar to plasma-derived FIX with sialic acid content consistent with the literature reports of good pharmacokinetic performance. These studies have shown that trenonacog alfa is a highly pure product with a primary sequence and posttranslational modifications consistent with the common Thr-148 polymorphism of plasma-derived FIX.

  9. Characterization of IXINITY® (Trenonacog Alfa), a Recombinant Factor IX with Primary Sequence Corresponding to the Threonine-148 Polymorph.

    Science.gov (United States)

    Monroe, Dougald M; Jenny, Richard J; Van Cott, Kevin E; Buhay, Shelly; Saward, Laura L

    2016-01-01

    The goal of these studies was to extensively characterize the first recombinant FIX therapeutic corresponding to the threonine-148 (Thr-148) polymorph, IXINITY (trenonacog alfa [coagulation factor IX (recombinant)]). Gel electrophoresis, circular dichroism, and gel filtration were used to determine purity and confirm structure. Chromatographic and mass spectrometry techniques were used to identify and quantify posttranslational modifications. Activity was assessed as the ability to activate factor X (FX) both with and without factor VIIIa (FVIIIa) and in a standard clotting assay. All results were consistent across multiple lots. Trenonacog alfa migrated as a single band on Coomassie-stained gels; activity assays were normal and showed factor IX (FIXa) per IU of FIX. The molecule has >97%  γ-carboxylation and underwent the appropriate structural change upon binding calcium ions. Trenonacog alfa was activated normally with factor XIa (FXIa); once activated it bound to FVIIIa and FXa. When activated to FIXa, it was inhibited efficiently by antithrombin. Glycosylation patterns were similar to plasma-derived FIX with sialic acid content consistent with the literature reports of good pharmacokinetic performance. These studies have shown that trenonacog alfa is a highly pure product with a primary sequence and posttranslational modifications consistent with the common Thr-148 polymorphism of plasma-derived FIX. PMID:26997955

  10. Recombinant Collagenlike Proteins

    Science.gov (United States)

    Fertala, Andzej

    2007-01-01

    A group of collagenlike recombinant proteins containing high densities of biologically active sites has been invented. The method used to express these proteins is similar to a method of expressing recombinant procollagens and collagens described in U. S. Patent 5,593,859, "Synthesis of human procollagens and collagens in recombinant DNA systems." Customized collagenous proteins are needed for biomedical applications. In particular, fibrillar collagens are attractive for production of matrices needed for tissue engineering and drug delivery. Prior to this invention, there was no way of producing customized collagenous proteins for these and other applications. Heretofore, collagenous proteins have been produced by use of such biological systems as yeasts, bacteria, and transgenic animals and plants. These products are normal collagens that can also be extracted from such sources as tendons, bones, and hides. These products cannot be made to consist only of biologically active, specific amino acid sequences that may be needed for specific applications. Prior to this invention, it had been established that fibrillar collagens consist of domains that are responsible for such processes as interaction with cells, binding of growth factors, and interaction with a number of structural proteins present in the extracellular matrix. A normal collagen consists of a sequence of domains that can be represented by a corresponding sequence of labels, e.g., D1D2D3D4. A collagenlike protein of the present invention contains regions of collagen II that contain multiples of a single domain (e.g., D1D1D1D1 or D4D4D4D4) chosen for its specific biological activity. By virtue of the multiplicity of the chosen domain, the density of sites having that specific biological activity is greater than it is in a normal collagen. A collagenlike protein according to this invention can thus be made to have properties that are necessary for tissue engineering.

  11. Primordial magnetogenesis before recombination

    CERN Document Server

    Fabre, Ophélia

    2015-01-01

    The origin of large magnetic fields in the Universe remains currently unknown. We investigate here a mechanism before recombination based on known physics. The source of the vorticity is due to the changes in the photon distribution function caused by the fluctuations in the background photons. We show that the magnetic field generated in the MHD limit, due to the Coulomb scattering, is of the order $10^{-49}$ G. We explicitly show that the magnetic fields generated from this process are sustainable and are not erased by resistive diffusion. We compare the results with current observations and discuss the implications.

  12. Primordial magnetogenesis before recombination

    Science.gov (United States)

    Fabre, Ophélia; Shankaranarayanan, S.

    2016-04-01

    The origin of large magnetic fields in the Universe remains currently unknown. We investigate here a mechanism before recombination based on known physics. The source of the vorticity is due to the changes in the photon distribution function caused by the fluctuations in the background photons. We show that the magnetic field generated in the MHD limit, due to the Coulomb scattering, is of the order 10-49 G on a coherence scale of 10 kpc. We explicitly show that the magnetic fields generated from this process are sustainable and are not erased by resistive diffusion. We compare the results with current observations and discuss the implications. Our seed magnetic fields are generated on small scales whereas the main mechanisms studied in the literature are on scale bigger than 1 Mpc. However, compared to more exotic theories generating seed magnetic fields on similar scales, the strength of our fields are generally smaller.

  13. Cell biology of mitotic recombination

    DEFF Research Database (Denmark)

    Lisby, Michael; Rothstein, Rodney

    2015-01-01

    Homologous recombination provides high-fidelity DNA repair throughout all domains of life. Live cell fluorescence microscopy offers the opportunity to image individual recombination events in real time providing insight into the in vivo biochemistry of the involved proteins and DNA molecules as w...

  14. Bimolecular recombination in organic photovoltaics.

    Science.gov (United States)

    Lakhwani, Girish; Rao, Akshay; Friend, Richard H

    2014-01-01

    The recombination of electrons and holes is a major loss mechanism in photovoltaic devices that controls their performance. We review scientific literature on bimolecular recombination (BR) in bulk heterojunction organic photovoltaic devices to bring forward existing ideas on the origin and nature of BR and highlight both experimental and theoretical work done to quantify its extent. For these systems, Langevin theory fails to explain BR, and recombination dynamics turns out to be dependent on mobility, temperature, electric field, charge carrier concentration, and trapped charges. Relationships among the photocurrent, open-circuit voltage, fill factor, and morphology are discussed. Finally, we highlight the recent emergence of a molecular-level picture of recombination, taking into account the spin and delocalization of charges. Together with the macroscopic picture of recombination, these new insights allow for a comprehensive understanding of BR and provide design principles for future materials and devices.

  15. Antithrombin-Ⅲ without concomitant heparin improves endotoxin-induced acute lung injury rats by inhibiting the activation of mitogen-activated protein kinase

    Institute of Scientific and Technical Information of China (English)

    SUN Hui-ming; HONG Ling-zhi; SHEN Xiao-kun; LIN Xin-qing; SONG Yong; SHI Yi

    2009-01-01

    Background Antithrombin-Ⅲ (AT-Ⅲ), the major inhibitor of thrombin in plasma, also has anti-inflammation property and might have positive effect on sepsis. The present study aimed to investigate the effects of AT-Ⅲ on inflammatory reaction and pulmonary protection in endotoxin-induced acute lung injury (ALI) rat.Methods Sixty male Sprague-Dawley rats were randomly assigned equally to normal control group, ALl group, AT-Ⅲ treatment group, AT-Ⅲ+heparin treatment group, and heparin treatment group. The pulmonary vascular permeability index (PVPI) was measured by single nuclide tracer technique. The activity of AT-Ⅲ in plasma was determined by the method of synthetic chromogenic substrata. Tumor necrosis factor-a (TNF-a) and interleukin-6 (IL-6) levels in serum were determined by enzyme-linked immunosorbent assay. The expressions of lung tissue mitogen-activated protein kinases (ERK1/2, P38 and JNK MAPK) were determined by Western blotting.Results Rats had significantly improved lung histopathology in the AT-Ⅲ treatment group and heparin treatment group compared with the ALI group. The PVPI of the ALI group was 0.38±0.04, significantly higher than that of the normal control group (0.20±0.02, P <0.01), AT-Ⅲ treatment group (0.30±0.04, P <0.01) and heparin treatment group (0.28±0.04,P <0.01) respectively. There were no significant differences of PVPI in the ALl group and AT-Ⅲ+heparin treatment group.The activity of AT-Ⅲ in plasma in the ALl group was (76±8)%, significantly lower than that of the normal control group ((96±11)%, P <0.05) and AT-Ill treatment group ((105±17)%, P <0.05) respectively. The serum levels of TNF-α and IL-6 of the ALI group were (2.770±0.373) pg/L and (1.615±0.128) ng/ml respectively, significantly higher than those of the normal control group ((0.506±0.093) pg/L and (0.233±0.047) ng/ml respectively, all P <0.01), AT-Ⅲ treatment group ((1.774±0.218) μg/L and (1.140±0145) ng/ml respectively, all P <0.01) and

  16. Analysis of interchromosomal mitotic recombination.

    Science.gov (United States)

    McGill, C B; Shafer, B K; Higgins, D R; Strathern, J N

    1990-07-01

    A novel synthetic locus is described that provides a simple assay system for characterizing mitotic recombinants. The locus consists of the TRP1 and HIS3 genes inserted into chromosome III of S. cerevisiae between the CRY1 and MAT loci. Defined trp1 and his3 alleles have been generated that allow the selection of interchromosomal recombinants in this interval. Trp+ or His+ recombinants can be divided into several classes based on coupling of the other alleles in the interval. The tight linkage of the CRY1 and MAT loci, combined with the drug resistance and cell type phenotypes that they respectively control, facilitates the classification of the recombinants without resorting to tetrad dissection. We present the distribution of spontaneous recombinants among the classes defined by this analysis. The data suggest that the recombination intermediate can have regions of symmetric strand exchange and that co-conversion tracts can extend over 1-3 kb. Continuous conversion tracts are favored over discontinuous tracts. The distribution among the classes defined by this analysis is altered in recombinants induced by UV irradiation.

  17. Aspergillus: sex and recombination.

    Science.gov (United States)

    Varga, János; Szigeti, Gyöngyi; Baranyi, Nikolett; Kocsubé, Sándor; O'Gorman, Céline M; Dyer, Paul S

    2014-12-01

    The genus Aspergillus is one of the most widespread groups of fungi on Earth, comprised of about 300-350 species with very diverse lifestyles. Most species produce asexual propagula (conidia) on conidial heads. Despite their ubiquity, a sexual cycle has not yet been identified for most of the aspergilli. Where sexual reproduction is present, species exhibit either homothallic (self fertile) or heterothallic (obligate outcrossing) breeding systems. A parasexual cycle has also been described in some Aspergillus species. As in other fungi, sexual reproduction is governed by mating-type (MAT) genes, which determine sexual identity and are involved in regulating later stages of sexual development. Previous population genetic studies have indicated that some supposedly asexual aspergilli exhibit evidence of a recombining population structure, suggesting the presence of a cryptic sexual cycle. In addition, genome analyses have revealed networks of genes necessary for sexual reproduction in several Aspergillus species, again consistent with latent sexuality in these fungi. Knowledge of MAT gene presence has then successfully been applied to induce sexual reproduction between MAT1-1 and MAT1-2 isolates of certain supposedly asexual aspergilli. Recent progress in understanding the extent and significance of sexual reproduction is described here, with special emphasis on findings that are relevant to clinically important aspergilli. PMID:25118872

  18. Ala384Ser polymorphism of antithrombin gene and pulmonary thromboembolism%抗凝血酶基因Ala384Ser多态性与肺血栓栓塞症相关性研究

    Institute of Scientific and Technical Information of China (English)

    白巧红; 刘锦铭; 王鹏; 乐军; 高蓓兰; 褚海青; 李霞; 桂涛

    2009-01-01

    Objective To investigate whether there is an association between the Ala384Ser polymorphsim of antithrombin gene and pulmonary thromboembolism (PTE). Methods Antit.hrombin Ala384Ser was detected by case-control study in 65 patients with PTE and 65 nonthrombosis normal individuals as controls. The antithrombin gene was amplified by polymerase chain reaction (PCR). The Ala384Ser polymorphism was genotyped by PCR-RFLP using Pvu Ⅱ ,and the confirmation of genotypes was performed by sequencing. Results There was significant difference in family history of PTE between China and West countries. There were no significant differences in the family of cardiovascular diseases, personal history of oral contraceptive, trauma,operation,cigarette smoking and alcohol drinking between patients and controls. Frequencies of allele G and T in the controls were 1,0 respectively. The distribution of genotypes met the Hardy-Weinberg equilibrium. There were no significant differences in the frequencies of genotype G/G,G/T and T/T between patients and controls. Conclusions Ala384Ser polymorphism of antithrombin gene is not a risk factor for PTE in Chinese,as the obvious discrepancy in the results with those reported by western country investigators may reflect the plausible pathogenic divergence in PTE among different races.%目的 探讨抗凝血酶基因Ala384Ser多态性与肺血栓栓塞症(pulmonary thromboembolism,PTE)的相关性.方法 采用病例对照研究的方法,运用聚合酶链反应扩增,产物纯化.Pvu Ⅱ限制性内切酶片段长度多态性聚合酶链反应及DNA测序技术对65例PTE患者及65名健康对照者进行抗凝血酶基因Ala384Ser分析.结果 PTE组仅3.3%患者有PTE家族史,这与西方人群报道结果存在显著差别;心血管疾病家族史、口服避孕药、吸烟、饮酒史、外伤及手术史PTE组与对照组比较差异无统计学意义.PTE组、对照组等位基因频率为1、0,符合Hardy-Weinberg平衡定律,G/G、G/T

  19. Controlled release from recombinant polymers.

    Science.gov (United States)

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-09-28

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed.

  20. Cell encoding recombinant human erythropoietin

    Energy Technology Data Exchange (ETDEWEB)

    Beck, A.K.; Withy, R.M.; Zabrecky, J.R.; Masiello, N.C.

    1990-09-04

    This patent describes a C127 cell transformed with a recombinant DNA vector. It comprises: a DNA sequence encoding human erythropoietin, the transformed cell being capable of producing N-linked and O-linked glycosylated human erythropoietin.

  1. Progenitors of Recombining Supernova Remnants

    OpenAIRE

    Moriya, Takashi J.

    2012-01-01

    Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with the ionization temperature higher than the electron temperature, is recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the superno...

  2. Recombinant snake venom prothrombin activators

    OpenAIRE

    Lövgren, Ann

    2012-01-01

    Three prothrombin activators; ecarin, which was originally isolated from the venom of the saw-scaled viper Echis carinatus, trocarin from the rough-scaled snake Tropidechis carinatus, and oscutarin from the Taipan snake Oxyuranus scutellatus, were expressed in mammalian cells with the purpose to obtain recombinant prothrombin activators that could be used to convert prothrombin to thrombin. We have previously reported that recombinant ecarin can efficiently generate thrombin without the need ...

  3. Plasmid recombination in Haemophilus influenzae

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, D.

    1982-01-01

    DNA recombination in exponential phase and competent Haemophilus influenzae was measured by an electron microscopic assay that relies on the conversion of plasmid RSF0885 monomers into multimeric forms. Dimer circles were present at a frequency of 2% in plasmid preparations from competent Rd (wild-type) cells; multimers were present at a frequency of 0.2% in preparations from exponential phase cells. Thus, plasmid recombination was stimulated in competent cells. Multimer formation occurred efficiently in cells of the transformation defective mutant rec2, implying that the rec2 gene product is not required for plasmid recombination. However, the absence of multimer plasmids in preparations from competent cells of the transformation defective mutant rec1 suggests that the rec1 gene product is required. Digestion of purified plasmids with restriction endonuclease PvuII, which makes a single cut in the monomer, revealed the presence of recombination intermediates composed of two linear plasmids joined to form two pairs of arms resembling the Greek letter chi. Length measurements of these arms taken from a population of recombination intermediates gave evidence that the plasmids were joined at sites of homology. The distributions of individual DNA strands, at the intersections of the four arms, could be resolved in some recombination intermediates and were of two types. The first type of junction appeared as a single-stranded arm appended to each corner. The second type of junction consisted of a single strand of DNA linking the two linear plasmids at a site of homology. The single-stranded linker was frequently situated at the edge of a short gap on one of the plasmids in the pair. The fine structures of the recombinational joints have been interpreted in terms of previously proposed models of recombination.

  4. Hemothorax under thrombolytic therapy with recombinant tissue: plasminogen activator (rt-PA) in a 16-year-old girl.

    Science.gov (United States)

    Varnholt, V; Ringe, H; Nietsch, L; Gaedicke, G

    1999-12-01

    We present the case of a 16-year-old girl with an extended thrombosis of the femoral and iliac vein and the inferior vena cava during pleuropneumonia; predisposing risk factors for thrombophilia were: use of contraceptives, nicotine abuse and congenital deficiency of antithrombin III (not previously diagnosed). Thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA; initial dose: 0.08 mg/kg/h) was started. 2 days later--after diagnosis of an extended hemothorax: 1500 ml blood were obtained after thoracocentesis, transfusion of packed red blood cells was necessary--rt-PA was stopped, with only heparin (400 U/kg/d) being administered. 36 h later--the thrombosis had not yet changed--the thrombolytic therapy with rt-PA was continued in a markedly reduced dose (0.015 mg/kg/d) with no further bleeding complications. 8 days later--after successful thrombolysis--t-PA was stopped, heparin was given for another 10 days, then cumarin was administered orally. PMID:10650854

  5. Recombinant snake venom prothrombin activators.

    Science.gov (United States)

    Lövgren, Ann

    2013-01-01

    Three prothrombin activators; ecarin, which was originally isolated from the venom of the saw-scaled viper Echis carinatus, trocarin from the rough-scaled snake Tropidechis carinatus, and oscutarin from the Taipan snake Oxyuranus scutellatus, were expressed in mammalian cells with the purpose to obtain recombinant prothrombin activators that could be used to convert prothrombin to thrombin. We have previously reported that recombinant ecarin can efficiently generate thrombin without the need for additional cofactors, but does not discriminate non-carboxylated prothrombin from biologically active γ-carboxylated prothrombin. Here we report that recombinant trocarin and oscutarin could not efficiently generate thrombin without additional protein co-factors. We confirm that both trocarin and oscutarin are similar to human coagulation Factor X (FX), explaining the need for additional cofactors. Sequencing of a genomic fragment containing 7 out of the 8 exons coding for oscutarin further confirmed the similarity to human FX. PMID:23111318

  6. Heterogeneity in recombinant protein production

    DEFF Research Database (Denmark)

    Schalén, Martin; Johanson, Ted; Lundin, Luisa;

    2012-01-01

    . the cell physiology is affected. Cells are stressed, and this may severely affect growth, by-product accumulation, biomass yield and recombinant product yield. The stress caused by exposure to divergent microenvironments, genetic differences of individual cells, differing cell cycle stage and cell age, all...... contribute to make a population in a fermenter heterogeneous, resulting in cell-to-cell variation in physiological parameters of the microbial culture. Our study aims at investigating how population heterogeneity and recombinant protein production is affected by environmental gradients in bioreactors...... are simulated in small bioreactors and the population heterogeneity can be visualised by analysing single cells with flow cytometry. This can give new insights to cell physiology and recombinant protein production at the industrial scale....

  7. The effect of a single recombination event

    DEFF Research Database (Denmark)

    Schierup, Mikkel Heide; Jensen, Thomas Mailund; Wiuf, Carsten

    We investigate the variance in how visible a single recombination event is in a SNP data set as a function of the type of recombination event and its age. Data is simulated under the coalescent with recombination and inference is by the popular composite likelihood methods. The major determinant...... of the effect of a recombination event is the genealogical type of the event and whether SNP variation is present that can reveal the genealogical consequences of the recombination event. Recombination events that only change some branch lengths in the genealogy have a very small, but detectable, effect....... The more lineages left when the recombination event occurs, the larger effect it has, implying that it is mainly young recombination events that we detect when estimating the rate. If the population is growing, though, more lineages are present back in time and relatively more ancient recombination events...

  8. Correlative Analysis of the Relationships and Differences on D-dimer, Fibrinogen and Antithrombin Ⅲ Between Varied Clinical Periods of Cerebral Infarction%D-D、Fb和AT-Ⅲ在脑梗死不同时期的变化及相关性分析

    Institute of Scientific and Technical Information of China (English)

    徐威香; 武蓉珍; 胡晓蕾

    2012-01-01

    目的:探讨血浆D-二聚体(D-D)、纤维蛋白原(Fb)和抗凝血酶Ⅲ(AT-Ⅲ)在脑梗死(CI)不同时期的变化及其临床意义.方法:根据临床特征,对260例CI患者进行分组,其中CI急性期组80例、进展期组41例、非进展期组65例、康复期组74例;90例体检健康者为正常对照组.采用SYSMEX CA7000血凝仪分别检测其血浆D-D、Fb和AT-Ⅲ水平.结果:CI急性期、进展期、非进展期患者D-D、Fb含量均明显高于正常对照组(P<0.01),AT-Ⅲ低于正常对照组(P<0.01);脑梗死组中,D-D与AT-Ⅲ呈负相关(P<0.01),D-D与Fb呈正相关(P<0.01),AT-Ⅲ与Fb无相关性.结论:CI患者D-D、Fb、AT-Ⅲ变化显著,D-D升高伴随AT-Ⅲ含量降低,提示D-D、Fb、AT-Ⅲ共同参与了梗死发生发展的病理生理过程,可作为CI临床危险分级和病情监测的指标.%Objective To investigate the differences and its clinical significance of D-dimer, fibrinogen and antithrombin Ⅲ between varied clinical periods of cerebral infarction( CI). Methods 328 CI patients were rolled into the study, and they were divided into four groups due to their different clinical periods as follows: group acute period (80) , group progressing(41) , group non-pro-gressing(65) , group convalescence(74). And, 90 healthy volunteers were rolled into the normal control group. Their plasma D-dimer, fibrinogen and antithrombin HI were detected on SYSMEX CA7000 automatic coagulation analyzer. Results D-dimer and fibrinogen of CI patients in the acute, progressing and non-progressing periods were significantly higher (P <0.01) than those of healthy volunteers, while antithrombin Ⅲ of them was significantly lower (P<0.01) than that of healthy volunteers. In CI patients, D-dimer correlated negatively with antithrombin Ⅲ, while positively with fibrinogen. No significant relationship was observed between antithrombin Ⅲ and fibrinogen. ConclUSin D-dimer, fibrinogen and antithrombin Ⅲ of CI patients varied significantly

  9. Preparing Recombinant Gonad Organ Cultures

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Blanche Capel and Jordan Batchvarov Corresponding author ([]()) ### INTRODUCTION It can be useful to assay migration between any two adjacent tissues during development. This protocol assays cell migration between the gonad and mesonephros using tissue recombination between genetically marked and unmarked tissue, combined with an organ culture technique. First, agar blocks are prepared in a custom-built mold. The size and sh...

  10. Controlled Release from Recombinant Polymers

    OpenAIRE

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-01-01

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and tempor...

  11. Live recombinant BHV/BRSV vaccine

    NARCIS (Netherlands)

    Keil, G.M.; Rijsewijk, F.A.M.

    1998-01-01

    The present invention refers to synthetic Bovine Respiratory Syncytium virus genes. Also the invention relates to live attenuated Bovine Herpesvirus recombinants carrying such synthetic genes. Furthermore, the invention relates to vaccines based on these live attenuated recombinants, for the protect

  12. Recombinant innovation and endogenous technological transitions

    NARCIS (Netherlands)

    K. Frenken; L.R. Izquierdo; P. Zeppini

    2012-01-01

    We propose a model of technological transitions based on two different types of innovations. Branching innovations refer to technological improvements along a particular path, while recombinant innovations represent fusions of multiple paths. Recombinant innovations create "short-cuts" which reduce

  13. Determination of recombination in Mycoplasma hominis

    DEFF Research Database (Denmark)

    Jacobsen, Iben Søgaard; Boesen, Thomas; Mygind, Tina;

    2002-01-01

    indicating the presence of recombination. In order to test for intergenic recombination, phylogenetic trees were reconstructed for each of the genes but no well-supported bifurcating phylogenetic trees could be obtained. The genes were tested for intragenic recombination using the correlation between linkage...

  14. Interstitial deletion of chromosome 1q [del(1)(q24q25.3)] identified by fluorescence in situ hybridization and gene dosage analysis of apolipoprotein A-II, coagulation factor V, and antithrombin III

    Energy Technology Data Exchange (ETDEWEB)

    Takano, Takako; Yamanouchi, Yasuko; Mori, Yosuke [Teikyo Univ. School of Medicine, Tokyo (Japan)] [and others

    1997-01-20

    We report on a 12-month-old Japanese boy with an interstitial deletion of the long-arm of chromosome 1 and meningomyelocele, hydrocephalus, anal atresia, atrial septal defect, left renal agenesis, bilateral cryptorchidism, talipes equinovarus, low birth weight, growth/developmental retardation, and many minor anomalies. By conventional GTG-banding, his karyotype was first interpreted as 46,XY,de1(1)(q23q24), but it was corrected as 46,XY.ish del(1)(q24q25.3) by fluorescence in situ hybridization using 11 known cosmid clones as probes. His serum levels of apolipoprotein A-II (gene symbol: APOA2, previously assigned to 1q21-q23) and coagulation factor V (F5, 1q21-q25) were normal, while serum concentration and activity of antithrombin III (AT3, 1q23-q25.1) was low. The results indicated that localization of APOA2 and F5 are proximal to the deleted region and AT3 is located within the deletion extent in the patient. 16 refs., 4 figs.

  15. Selection of Recombinant Human Antibodies.

    Science.gov (United States)

    Tomszak, Florian; Weber, Susanne; Zantow, Jonas; Schirrmann, Thomas; Hust, Michael; Frenzel, André

    2016-01-01

    Since the development of therapeutic antibodies the demand of recombinant human antibodies is steadily increasing. Traditionally, therapeutic antibodies were generated by immunization of rat or mice, the generation of hybridoma clones, cloning of the antibody genes and subsequent humanization and engineering of the lead candidates. In the last few years, techniques were developed that use transgenic animals with a human antibody gene repertoire. Here, modern recombinant DNA technologies can be combined with well established immunization and hybridoma technologies to generate already affinity maturated human antibodies. An alternative are in vitro technologies which enabled the generation of fully human antibodies from antibody gene libraries that even exceed the human antibody repertoire. Specific antibodies can be isolated from these libraries in a very short time and therefore reduce the development time of an antibody drug at a very early stage.In this review, we describe different technologies that are currently used for the in vitro and in vivo generation of human antibodies. PMID:27236551

  16. Mechanisms of sister chromatid recombination

    International Nuclear Information System (INIS)

    Studies using T948 as a model system have been carried out aimed at elucidating the mechanism of sister chromatid recombination (SCR). Characterization of U.V. light- and x-ray-induced SCR, the relationiship between SCR induction and DNA repair using rad mutations, and the relationship between SCR induction and the time of cell division using cdc mutations are presented. It has been supposed that SCR is induced at the phase of S-G2 following DNA replication, that postreplication break of DNA strands is strongly involved in the induction of SCR, and that induction type of SCR, i.e., conversion type or recombination type, is dependent upon the type of molecular damage of DNA. (Namekawa, K.)

  17. Recombinant erythropoietin in clinical practice

    OpenAIRE

    Ng, T; Marx, G.; Littlewood, T; Macdougall, I

    2003-01-01

    The introduction of recombinant human erythropoietin (RHuEPO) has revolutionised the treatment of patients with anaemia of chronic renal disease. Clinical studies have demonstrated that RHuEPO is also useful in various non-uraemic conditions including haematological and oncological disorders, prematurity, HIV infection, and perioperative therapies. Besides highlighting both the historical and functional aspects of RHuEPO, this review discusses the applications of RHuEPO in clinical practice a...

  18. Recombinant antibodies and tumor targeting

    OpenAIRE

    Sheikholvaezin, Ali

    2006-01-01

    Different antibody derived constructs are rapidly advancing as putative tools for treatment of malignant diseases. Antibody engineering has added significant new technologies to modify size, affinities, solubility, stability and biodistribution properties for immunoconjugates. In the present thesis, the aim was to increase our knowledge on how new recombinant antibodies could be tailored to optimize localization to experimental tumors in mice. One hybridoma, producing the monoclonal antibody ...

  19. Workshop on Radio Recombination Lines

    CERN Document Server

    1980-01-01

    Since their first detection 15 years ago, radio recombination lines from several elements have been observed in a wide variety of objects including HII regions, planetary nebulae, molecular clouds, the diffuse interstellar medium, and recently, other galaxies. The observations span almost the entire range from 0.1 to 100 GHz, and employ both single­ djsh and aperture synthesis techniques. The theory of radio recombination lines has also advanced strongly, to the point where it is perhaps one of the best-understood in astro­ physics. In a parallel development, it has become possible over the last decade to study these same highly-excited atoms in the laboratory; this work provides further confirmation of the theoretical framework. However there has been continuing controversy over the astrophysical interpre­ tation of radio recombination line observations, especially regarding the role of stimulated emission. A workshop was held in Ottawa on 24-25 August, 1979, bringing together many of the active scientist...

  20. Nondisjunction of chromosome 15: Origin and recombination

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, W.P.; Bernasconi, F.; Schinzel, A.A.; Mutirangura, A.; Ledbetter, D.H. (Baylor College of Medicine, Houston, TX (United States)); Langlois, S. (Univ. of Britisch Columbia, Vancouver (Canada)); Morris, M.A.; Malcolm, S.

    1993-09-01

    Thirty-two cases of uniparental disomy (UPD), ascertained from Prader-Willi syndrome patients (N=27) and Angelman syndrome patients (N-5), are used to investigate the pattern of recombination associated with nondisjunction of chromosome 15. In addition, the meiotic stage of nondisjunction is inferred by using markers mapping near the centromere. Two basic approaches to the analysis of recombination in specific pairwise intervals along the chromosome. This method shows a significant reduction in recombination for two of five intervals examined. Second, the observed frequency of each recombinant class (i.e., zero, one, two, three, or more observable crossovers) is compared with expected values. This is useful for testing whether the reduction in recombination can be attributed solely to a proportion of cases with no recombination at all (because of asynapsis), with the remaining groups showing normal recombination (or even excess recombination), or whether recombination is uniformly reduced. Analysis of maternal UPD(15) data shows a slight reduction in the multiple-recombinant classes, with a corresponding increase in both the zero- and one-recombinant classes over expected values. The majority, more than 82%, of the extra chromosomes in maternal UPD(15) cases are due to meiotic I nondisjunction events. In contrast, more paternal UPD(15) cases so far examined appear to have a postzygotic origin of the extra paternal chromosome. 33 refs., 1 fig., 7 tabs.

  1. Bacteriophage recombination systems and biotechnical applications.

    Science.gov (United States)

    Nafissi, Nafiseh; Slavcev, Roderick

    2014-04-01

    Bacteriophage recombination systems have been widely used in biotechnology for modifying prokaryotic species, for creating transgenic animals and plants, and more recently, for human cell gene manipulation. In contrast to homologous recombination, which benefits from the endogenous recombination machinery of the cell, site-specific recombination requires an exogenous source of recombinase in mammalian cells. The mechanism of bacteriophage evolution and their coexistence with bacterial cells has become a point of interest ever since bacterial viruses' life cycles were first explored. Phage recombinases have already been exploited as valuable genetic tools and new phage enzymes, and their potential application to genetic engineering and genome manipulation, vectorology, and generation of new transgene delivery vectors, and cell therapy are attractive areas of research that continue to be investigated. The significance and role of phage recombination systems in biotechnology is reviewed in this paper, with specific focus on homologous and site-specific recombination conferred by the coli phages, λ, and N15, the integrase from the Streptomyces phage, ΦC31, the recombination system of phage P1, and the recently characterized recombination functions of Yersinia phage, PY54. Key steps of the molecular mechanisms involving phage recombination functions and their application to molecular engineering, our novel exploitations of the PY54-derived recombination system, and its application to the development of new DNA vectors are discussed.

  2. Bacteriophage recombination systems and biotechnical applications.

    Science.gov (United States)

    Nafissi, Nafiseh; Slavcev, Roderick

    2014-04-01

    Bacteriophage recombination systems have been widely used in biotechnology for modifying prokaryotic species, for creating transgenic animals and plants, and more recently, for human cell gene manipulation. In contrast to homologous recombination, which benefits from the endogenous recombination machinery of the cell, site-specific recombination requires an exogenous source of recombinase in mammalian cells. The mechanism of bacteriophage evolution and their coexistence with bacterial cells has become a point of interest ever since bacterial viruses' life cycles were first explored. Phage recombinases have already been exploited as valuable genetic tools and new phage enzymes, and their potential application to genetic engineering and genome manipulation, vectorology, and generation of new transgene delivery vectors, and cell therapy are attractive areas of research that continue to be investigated. The significance and role of phage recombination systems in biotechnology is reviewed in this paper, with specific focus on homologous and site-specific recombination conferred by the coli phages, λ, and N15, the integrase from the Streptomyces phage, ΦC31, the recombination system of phage P1, and the recently characterized recombination functions of Yersinia phage, PY54. Key steps of the molecular mechanisms involving phage recombination functions and their application to molecular engineering, our novel exploitations of the PY54-derived recombination system, and its application to the development of new DNA vectors are discussed. PMID:24442504

  3. CRMAGE: CRISPR Optimized MAGE Recombineering

    DEFF Research Database (Denmark)

    Ronda, Carlotta; Pedersen, Lasse Ebdrup; Sommer, Morten Otto Alexander;

    2016-01-01

    A bottleneck in metabolic engineering and systems biology approaches is the lack of efficient genome engineering technologies. Here, we combine CRISPR/Cas9 and λ Red recombineering based MAGE technology (CRMAGE) to create a highly efficient and fast method for genome engineering of Escherichia coli...... that are assembled by a USER-cloning approach enabling quick and cost efficient gRNA replacement. CRMAGE furthermore utilizes CRISPR/Cas9 for efficient plasmid curing, thereby enabling multiple engineering rounds per day. To facilitate the design process, a web-based tool was developed to predict both the λ Red...

  4. Comparison of 2 synthetically generated recombinant prions

    OpenAIRE

    Zhang, Yi; Wang, Fei; Wang, Xinhe; Zhang, Zhihong; Xu, Yuanyuan; Yu, Guohua; Yuan, Chonggang; Ma, Jiyan

    2014-01-01

    Prion is a protein-conformation-based infectious agent causing fatal neurodegenerative diseases in humans and animals. Our previous studies revealed that in the presence of cofactors, infectious prions can be synthetically generated in vitro with bacterially expressed recombinant prion protein (PrP). Once initiated, the recombinant prion is able to propagate indefinitely via serial protein misfolding cyclic amplification (sPMCA). In this study, we compared 2 separately initiated recombinant p...

  5. How well do we understand cosmological recombination?

    OpenAIRE

    Wong, Wan Yan; Moss, Adam; Scott, Douglas

    2007-01-01

    The major theoretical limitation for extracting cosmological parameters from the CMB sky lies in the precision with which we can calculate the cosmological recombination process. Uncertainty in the details of hydrogen and helium recombination could effectively increase the errors or bias the values of the cosmological parameters derived from the Planck satellite, for example. Here we modify the cosmological recombination code RECFAST by introducing one more parameter to reproduce the recent n...

  6. Role of ubiquitination in meiotic recombination repair

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Programmed and unprogrammed double-strand breaks (DSBs) often arise from such physiological requirements as meiotic recombination, and exogenous insults, such as ionizing radiation (IR). Due to deleterious impacts on genome stability, DSBs must be appropriately processed and repaired in a regulatory manner. Recent investigations have indicated that ubiquitination is a critical factor in DNA damage response and meiotic recombination repair. This review summarizes the effects of proteins and complexes associated with ubiquitination with regard to homologous recombination (HR)-dependent DSB repair.

  7. Rapid purification of recombinant histones.

    Directory of Open Access Journals (Sweden)

    Henrike Klinker

    Full Text Available The development of methods to assemble nucleosomes from recombinant histones decades ago has transformed chromatin research. Nevertheless, nucleosome reconstitution remains time consuming to this day, not least because the four individual histones must be purified first. Here, we present a streamlined purification protocol of recombinant histones from bacteria. We termed this method "rapid histone purification" (RHP as it circumvents isolation of inclusion bodies and thereby cuts out the most time-consuming step of traditional purification protocols. Instead of inclusion body isolation, whole cell extracts are prepared under strongly denaturing conditions that directly solubilize inclusion bodies. By ion exchange chromatography, the histones are purified from the extracts. The protocol has been successfully applied to all four canonical Drosophila and human histones. RHP histones and histones that were purified from isolated inclusion bodies had similar purities. The different purification strategies also did not impact the quality of octamers reconstituted from these histones. We expect that the RHP protocol can be readily applied to the purification of canonical histones from other species as well as the numerous histone variants.

  8. Human Insulin from Recombinant DNA Technology

    Science.gov (United States)

    Johnson, Irving S.

    1983-02-01

    Human insulin produced by recombinant DNA technology is the first commercial health care product derived from this technology. Work on this product was initiated before there were federal guidelines for large-scale recombinant DNA work or commercial development of recombinant DNA products. The steps taken to facilitate acceptance of large-scale work and proof of the identity and safety of such a product are described. While basic studies in recombinant DNA technology will continue to have a profound impact on research in the life sciences, commercial applications may well be controlled by economic conditions and the availability of investment capital.

  9. Recombinant Factor IX Fc Fusion Protein Maintains Full Procoagulant Properties and Exhibits Prolonged Efficacy in Hemophilia B Mice.

    Directory of Open Access Journals (Sweden)

    Garabet G Toby

    Full Text Available Hemophilia B is an inherited X chromosome-linked disorder characterized by impaired blood clotting owing to the absence of functional coagulation factor IX. Due to the relatively short half-life of factor IX, patients with hemophilia B require frequent factor IX infusions to maintain prophylaxis. We have developed a recombinant factor IX (rFIX fused to the Fc region of IgG (rFIXFc with an extended half-life in animals and humans.Procoagulant properties of rFIXFc and rFIX (BENEFIX® were compared to determine the effect of the Fc region on rFIXFc hemostatic function. Specifically, we assessed rFIXFc activation, intermolecular interactions within the Xase complex, inactivation by antithrombin III (AT and thrombin generation potential compared with rFIX. We also assessed the acute and prophylactic efficacy profiles of rFIXFc and rFIX in vivo in hemophilia B mouse bleeding models.The activation by factor XIa or factor VIIa/tissue factor, inhibition by AT, interaction profiles with phospholipids, affinities for factor VIIIa within the context of the Xase complex, and thrombin generation profiles were similar for rFIXFc and rFIX. Xase complexes formed with either molecule exhibited similar kinetic profiles for factor Xa generation. In acute efficacy models, mice infused with rFIXFc or rFIX were equally protected from bleeding. However, in prophylactic efficacy models, protection from bleeding was maintained approximately three times longer in rFIXFc-dosed mice than in those given rFIX; this prolonged efficacy correlates with the previously observed half-life extension. We conclude that rFIXFc retains critical FIX procoagulant attributes and that the extension in rFIXFc half-life translates into prolonged efficacy in hemophilia B mice.

  10. Fundamental Studies of Recombinant Hydrogenases

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Michael W

    2014-01-25

    This research addressed the long term goals of understanding the assembly and organization of hydrogenase enzymes, of reducing them in size and complexity, of determining structure/function relationships, including energy conservation via charge separation across membranes, and in screening for novel H2 catalysts. A key overall goal of the proposed research was to define and characterize minimal hydrogenases that are produced in high yields and are oxygen-resistant. Remarkably, in spite of decades of research carried out on hydrogenases, it is not possible to readily manipulate or design the enzyme using molecular biology approaches since a recombinant form produced in a suitable host is not available. Such resources are essential if we are to understand what constitutes a “minimal” hydrogenase and design such catalysts with certain properties, such as resistance to oxygen, extreme stability and specificity for a given electron donor. The model system for our studies is Pyrococcus furiosus, a hyperthermophile that grows optimally at 100°C, which contains three different nickel-iron [NiFe-] containing hydrogenases. Hydrogenases I and II are cytoplasmic while the other, MBH, is an integral membrane protein that functions to both evolve H2 and pump protons. Three important breakthroughs were made during the funding period with P. furiosus soluble hydrogenase I (SHI). First, we produced an active recombinant form of SHI in E. coli by the co-expression of sixteen genes using anaerobically-induced promoters. Second, we genetically-engineered P. furiosus to overexpress SHI by an order of magnitude compared to the wild type strain. Third, we generated the first ‘minimal’ form of SHI, one that contained two rather than four subunits. This dimeric form was stable and active, and directly interacted with a pyruvate-oxidizing enzyme with any intermediate electron carrier. The research resulted in five peer-reviewed publications.

  11. Titania Photocatalysis beyond Recombination: A Critical Review

    Directory of Open Access Journals (Sweden)

    Bunsho Ohtani

    2013-11-01

    Full Text Available This short review paper shows the significance of recombination of a photoexcited electron and a hole in conduction and valence bands, respectively, of a titania photocatalyst, since recombination has not yet been fully understood and has not been evaluated adequately during the past several decades of research on heterogeneous photocatalysis.

  12. Recombinant organisms for production of industrial products

    OpenAIRE

    Adrio, Jose-Luis; Demain, Arnold L.

    2009-01-01

    A revolution in industrial microbiology was sparked by the discoveries of ther double-stranded structure of DNA and the development of recombinant DNA technology. Traditional industrial microbiology was merged with molecular biology to yield improved recombinant processes for the industrial production of primary and secondary metabolites, protein biopharmaceuticals and industrial enzymes. Novel genetic techniques such as metabolic engineering, combinatorial biosynthesis and molecular breeding...

  13. RNAi and heterochromatin repress centromeric meiotic recombination

    DEFF Research Database (Denmark)

    Ellermeier, Chad; Higuchi, Emily C; Phadnis, Naina;

    2010-01-01

    to genetic disabilities, including birth defects. The basis by which centromeric meiotic recombination is repressed has been largely unknown. We report here that, in fission yeast, RNAi functions and Clr4-Rik1 (histone H3 lysine 9 methyltransferase) are required for repression of centromeric recombination...

  14. Cell biology of homologous recombination in yeast

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine Valerie; Rothstein, Rodney; Lisby, Michael

    2011-01-01

    Homologous recombination is an important pathway for error-free repair of DNA lesions, such as single- and double-strand breaks, and for rescue of collapsed replication forks. Here, we describe protocols for live cell imaging of single-lesion recombination events in the yeast Saccharomyces cerevi...

  15. Theoretic Study of CⅡ Recombination Line

    Institute of Scientific and Technical Information of China (English)

    彭永伦; 王民盛; 韩小英; 李家明

    2004-01-01

    Using the R-matrix method, we carry out theoretical calculations for recombination line λ 8794 A(3d'-3p') of CⅡ, which is important to estimate the abundances of carbon in planetary nebulae. Our calculations are based on three sets of target orbital basis, through which we elucidate the electron correlation and static polarization effects in the dielectronic recombination processes.

  16. Electron-ion recombination at low energy

    International Nuclear Information System (INIS)

    The work is based on results obtained with a merged-beams experiment. A beam of electronics with a well characterized density and energy distribution was merged with a fast, monoenergetic ion beam. Results have been obtained for radiative recombination and dielectronic recombination at low relative energies (0 to ∼70eV). The obtained energy resolution was improved by about a factor of 30. High vacuum technology was used to suppress interactions with electrons from the environments. The velocity distribution of the electron beam was determined. State-selective dielectronic-recombination measurements were performable. Recombination processes were studied. The theoretical background for radiative recombination and Kramers' theory are reviewed. The quantum mechanical result and its relation to the semiclassical theory is discussed. Radiative recombination was also measured with several different non-bare ions, and the applicability of the semiclassical theory to non-bare ions was investigated. The use of an effective charge is discussed. For dielectronic recombination, the standard theoretical approach in the isolated resonance and independent-processes approximation is debated. The applicability of this method was tested. The theory was able to reproduce most of the experimental data except when the recombination process was sensitive to couplings between different electronic configurations. The influence of external perturbing electrostatic fields is discussed. (AB) (31 refs.)

  17. Electron Recombination in a Dense Hydrogen Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jana, M.R.; Johnstone, C.; Kobilarcik, T.; Koizumi, G.M.; Moretti, A.; Popovic, M.; Tollestrup, A.V.; Yonehara, K.; /Fermilab; Leonova, M.A.; Schwarz, T.A.; /Fermilab; Chung, M.; /Unlisted /IIT, Chicago /Fermilab /MUONS Inc., Batavia /Turin Polytechnic

    2012-05-01

    A high pressure hydrogen gas filled RF cavity was subjected to an intense proton beam to study the evolution of the beam induced plasma inside the cavity. Varying beam intensities, gas pressures and electric fields were tested. Beam induced ionized electrons load the cavity, thereby decreasing the accelerating gradient. The extent and duration of this degradation has been measured. A model of the recombination between ionized electrons and ions is presented, with the intent of producing a baseline for the physics inside such a cavity used in a muon accelerator. Analysis of the data taken during the summer of 2011 shows that self recombination takes place in pure hydrogen gas. The decay of the number of electrons in the cavity once the beam is turned off indicates self recombination rather than attachment to electronegative dopants or impurities. The cross section of electron recombination grows for larger clusters of hydrogen and so at the equilibrium of electron production and recombination in the cavity, processes involving H{sub 5}{sup +} or larger clusters must be taking place. The measured recombination rates during this time match or exceed the analytic predicted values. The accelerating gradient in the cavity recovers fully in time for the next beam pulse of a muon collider. Exactly what the recombination rate is and how much the gradient degrades during the 60 ns muon collider beam pulse will be extrapolated from data taken during the spring of 2012.

  18. Initiation of meiotic recombination in Ustilago maydis.

    Science.gov (United States)

    Kojic, Milorad; Sutherland, Jeanette H; Pérez-Martín, José; Holloman, William K

    2013-12-01

    A central feature of meiosis is the pairing and recombination of homologous chromosomes. Ustilago maydis, a biotrophic fungus that parasitizes maize, has long been utilized as an experimental system for studying recombination, but it has not been clear when in the life cycle meiotic recombination initiates. U. maydis forms dormant diploid teliospores as the end product of the infection process. Upon germination, teliospores complete meiosis to produce four haploid basidiospores. Here we asked whether the meiotic process begins when teliospores germinate or at an earlier stage in development. When teliospores homozygous for a cdc45 mutation temperature sensitive for DNA synthesis were germinated at the restrictive temperature, four nuclei became visible. This implies that teliospores have already undergone premeiotic DNA synthesis and suggests that meiotic recombination initiates at a stage of infection before teliospores mature. Determination of homologous recombination in plant tissue infected with U. maydis strains heteroallelic for the nar1 gene revealed that Nar(+) recombinants were produced at a stage before teliospore maturation. Teliospores obtained from a spo11Δ cross were still able to germinate but the process was highly disturbed and the meiotic products were imbalanced in chromosomal complement. These results show that in U. maydis, homologous recombination initiates during the infection process and that meiosis can proceed even in the absence of Spo11, but with loss of genomic integrity.

  19. Optimal Expression Condition of Recombinant RAP

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; ZHANG Hong; BI Hao; LIU Zhiguo; GUO Jianli; QU Shen

    2007-01-01

    In order to construct the expression recombinant of human receptor associated protein (RAP), optimize its expression condition and obtain the recombinant protein after expression with high efficiency, two prokaryotic expression vectors-pT7-PL and pET-28a(+) were used to construct the expression recombinant containing RAP cDNA, and the expression efficiency of two kinds of expression E. coli of BL21 strains was compared. The effect of different induction conditions on the expression of recombinant RAP was observed. After recombinant protein was purified with Ni+-nitrilotriacetic acid (Ni+-NTA) affinity chromatogram, its binding ability with microphage was observed. The results showed that two recombinant plasmids both obtained high expression of RAP. The expression levels of RAP in plasmid pT7-PL-RAP in BL21 (DE3, plysS) strain were significantly higher than in BL21 (DE3) strain. The expression of pT7-PL-RAP in the presence of chloramphenicol was higher than in the absence of chloramphenicol, and most of the inducible expressed RAP was soluble. The RAP which was purified by Ni+-NTA resin could strongly bind with the RAW264.7 cells rich in low density lipoprotein receptor (LDLR) family receptors. It was concluded that the expression condition of recombinant RAP was optimized and functional RAP was obtained, which offered a good foundation for the further production of RAP as research tool.

  20. Changes of thrombin-antithrombin complex and other variables in acute respiratory distress syndrome%急性呼吸窘迫综合征中的凝血酶-抗凝血酶等指标的变化

    Institute of Scientific and Technical Information of China (English)

    高志国

    2008-01-01

    目的 探讨D-二聚体、凝血酶-抗凝血酶复合物、纤溶酶-抗纤溶酶复合物、蛋白C在急性呼吸窘迫综合征(ARDS)诊断中临床意义,并为ARDS治疗过程提供血清学依据.方法 实验组选取105例符合ARDS诊断标准患者(对照组选取健康献血员)分别采静脉血,进行凝血酶原时间、凝血酶时间、部分凝血活酶时同、血小板计数、D-D、TAT、PAP、PC八项血清指标的定量测定.结果 ARDS的患者血浆中D-D、TAT、PAP、PC的含量与对照组进行比较,差异有统计学意义(P<0.01).结论 D-D、TAT、PAP、PC浓度在ARDS患者中有明显变化,而PT、TT、APTT、Pt的含量变化不明显.提示在ARDS早期给予抗凝治疗有一定的临床价值.%Objective To measure D-Dimer(DD) ,thrombin-antithrombin complex(TAT), lasmin-antiplasrain complex(PAP) and protein C(PC) in ARDS,to find the clinical significance of them,discuss the objective base in the early diagnosis of ARDS in the lab, and offer the serologic bases in the treatment and prognosis of ARDS.Methods 105 patients of ARDS were selected as the study group, and 105 people were selected as the control group, all of whom were healthy with no thrombus diseases. The venous blood of everyone in both groups was sampied,in order to take a quantitative determination of plasma prothrombin time(PT), prothrombin time(TT), kadin partial thromboplastin time(APTT), the amount of blood platelet, DD, TAT, PAP, PC. Results Serum concentratation of D-D, TAT, PAP was significantly higher in patients in ARDS group than that in control group(P<0.01).Serum concentratation of PC was significantly lower in patients in ARDS group than that in control group (P<0.01). Conclusion Measuring the concentration of DD, TAT, PAP and PC was very important, which not only did good to the early diagnosis of ARDS,but also had a clinic value.

  1. Recombination every day: abundant recombination in a virus during a single multi-cellular host infection.

    Directory of Open Access Journals (Sweden)

    Remy Froissart

    2005-03-01

    Full Text Available Viral recombination can dramatically impact evolution and epidemiology. In viruses, the recombination rate depends on the frequency of genetic exchange between different viral genomes within an infected host cell and on the frequency at which such co-infections occur. While the recombination rate has been recently evaluated in experimentally co-infected cell cultures for several viruses, direct quantification at the most biologically significant level, that of a host infection, is still lacking. This study fills this gap using the cauliflower mosaic virus as a model. We distributed four neutral markers along the viral genome, and co-inoculated host plants with marker-containing and wild-type viruses. The frequency of recombinant genomes was evaluated 21 d post-inoculation. On average, over 50% of viral genomes recovered after a single host infection were recombinants, clearly indicating that recombination is very frequent in this virus. Estimates of the recombination rate show that all regions of the genome are equally affected by this process. Assuming that ten viral replication cycles occurred during our experiment-based on data on the timing of coat protein detection-the per base and replication cycle recombination rate was on the order of 2 x 10(-5 to 4 x 10(-5. This first determination of a virus recombination rate during a single multi-cellular host infection indicates that recombination is very frequent in the everyday life of this virus.

  2. Recombination analysis of Soybean mosaic virus sequences reveals evidence of RNA recombination between distinct pathotypes

    Directory of Open Access Journals (Sweden)

    Babu Mohan

    2008-11-01

    Full Text Available Abstract RNA recombination is one of the two major factors that create RNA genome variability. Assessing its incidence in plant RNA viruses helps understand the formation of new isolates and evaluate the effectiveness of crop protection strategies. To search for recombination in Soybean mosaic virus (SMV, the causal agent of a worldwide seed-borne, aphid-transmitted viral soybean disease, we obtained all full-length genome sequences of SMV as well as partial sequences encoding the N-terminal most (P1 protease and the C-terminal most (capsid protein; CP viral protein. The sequences were analyzed for possible recombination events using a variety of automatic and manual recombination detection and verification approaches. Automatic scanning identified 3, 10, and 17 recombination sites in the P1, CP, and full-length sequences, respectively. Manual analyses confirmed 10 recombination sites in three full-length SMV sequences. To our knowledge, this is the first report of recombination between distinct SMV pathotypes. These data imply that different SMV pathotypes can simultaneously infect a host cell and exchange genetic materials through recombination. The high incidence of SMV recombination suggests that recombination plays an important role in SMV evolution. Obtaining additional full-length sequences will help elucidate this role.

  3. Recombination every day: abundant recombination in a virus during a single multi-cellular host infection.

    Science.gov (United States)

    Froissart, Remy; Roze, Denis; Uzest, Marilyne; Galibert, Lionel; Blanc, Stephane; Michalakis, Yannis

    2005-03-01

    Viral recombination can dramatically impact evolution and epidemiology. In viruses, the recombination rate depends on the frequency of genetic exchange between different viral genomes within an infected host cell and on the frequency at which such co-infections occur. While the recombination rate has been recently evaluated in experimentally co-infected cell cultures for several viruses, direct quantification at the most biologically significant level, that of a host infection, is still lacking. This study fills this gap using the cauliflower mosaic virus as a model. We distributed four neutral markers along the viral genome, and co-inoculated host plants with marker-containing and wild-type viruses. The frequency of recombinant genomes was evaluated 21 d post-inoculation. On average, over 50% of viral genomes recovered after a single host infection were recombinants, clearly indicating that recombination is very frequent in this virus. Estimates of the recombination rate show that all regions of the genome are equally affected by this process. Assuming that ten viral replication cycles occurred during our experiment-based on data on the timing of coat protein detection-the per base and replication cycle recombination rate was on the order of 2 x 10(-5) to 4 x 10(-5). This first determination of a virus recombination rate during a single multi-cellular host infection indicates that recombination is very frequent in the everyday life of this virus. PMID:15737066

  4. Genetic Analyses of Meiotic Recombination in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Meiosis is essential for sexual reproduction and recombination is a critical step required for normal meiosis. Understanding the underlying molecular mechanisms that regulate recombination ie important for medical, agricultural and ecological reasons. Readily available molecular and cytological tools make Arabidopsis an excellent system to study meiosis. Here we review recent developments in molecular genetic analyses on meiotic recombination. These Include studies on plant homologs of yeast and animal genes, as well as novel genes that were first identified in plants. The characterizations of these genes have demonstrated essential functions from the initiation of recombination by double-strand breaks to repair of such breaks, from the formation of double-Holliday junctions to possible resolution of these junctions, both of which are critical for crossover formation. The recent advances have ushered a new era in plant meiosis, in which the combination of genetics, genomics, and molecular cytology can uncover important gene functions.

  5. Recombinant allergens: what does the future hold?

    Science.gov (United States)

    Valenta, Rudolf; Niespodziana, Katarzyna; Focke-Tejkl, Margit; Marth, Katharina; Huber, Hans; Neubauer, Angela; Niederberger, Verena

    2011-04-01

    This year we are celebrating not only the centenary of allergen-specific immunotherapy but also the 10-year anniversary of the first administration of recombinant allergen-based vaccines to allergic patients. By using recombinant DNA technology, defined and safe allergy vaccines can be produced that allow us to overcome many, if not all, of the problems associated with the use of natural allergen extracts, such as insufficient quality, allergenic activity, and poor immunogenicity. Here we provide an update of clinical studies with recombinant allergen-based vaccines, showing that some of these vaccines have undergone successful clinical evaluation up to phase III studies. Furthermore, we introduce a strategy for allergen-specific immunotherapy based on recombinant fusion proteins consisting of viral carrier proteins and allergen-derived peptides without allergenic activity, which holds the promise of being free of side effects and eventually being useful for prophylactic vaccination.

  6. Recombinant Human Papillomavirus (HPV) Nonavalent Vaccine

    Science.gov (United States)

    This page contains brief information about recombinant human papillomavirus (HPV) nonavalent vaccine and a collection of links to more information about the use of this vaccine, research results, and ongoing clinical trials.

  7. Recombinant Human Papillomavirus (HPV) Bivalent Vaccine

    Science.gov (United States)

    This page contains brief information about recombinant human papillomavirus (HPV) bivalent vaccine and a collection of links to more information about the use of this vaccine, research results, and ongoing clinical trials.

  8. Recombinant Human Papillomavirus (HPV) Quadrivalent Vaccine

    Science.gov (United States)

    This page contains brief information about recombinant human papillomavirus (HPV) quadrivalent vaccine and a collection of links to more information about the use of this vaccine, research results, and ongoing clinical trials.

  9. Regulation of Homologous Recombination by SUMOylation

    DEFF Research Database (Denmark)

    Pinela da Silva, Sonia Cristina

    factors such as the homologous recombination (HR) machinery. HR constitutes the main DSB repair pathway in Saccharomyces cerevisiae and despite being largely considered an error-free process and essential for genome stability, uncontrolled recombination can lead to loss of heterozygosity, translocations....... In this study I present new insights for the role of SUMOylation in regulating HR by dissecting the role of SUMO in the interaction between the central HR-mediator protein Rad52 and its paralogue Rad59 and the outcome of recombination. This data provides evidence for the importance of SUMO in promoting protein......-protein interactions at the sites of repair, enabling effective Rad51-mediated recombination through the concerted action of the Rad52-Rad59 complex and the helicase Srs2. In addition, I also peer into the role of Rad52 SUMOylation in the context of persistent DSBs and telomere homeostasis. Furthermore, I characterize...

  10. Hadron Correlations from Recombination and Fragmentation

    CERN Document Server

    Fries, R J

    2005-01-01

    We review the formalism of quark recombination applied to the hadronization of a quark gluon plasma. Evidence in favor of the quark recombination model is outlined. Recent work on parton correlations, leading to detectable correlations between hadrons, is discussed. Hot spots from completely quenched jets are a likely source of such correlations which appear to be jet-like. It will be discussed how such a picture compares with measurement of associated hadron yields at RHIC.

  11. Signals From the Epoch of Cosmological Recombination

    OpenAIRE

    Sunyaev, R. A.; Chluba, J.

    2009-01-01

    The physical ingredients to describe the epoch of cosmological recombination are amazingly simple and well-understood. This fact allows us to take into account a very large variety of physical processes, still finding potentially measurable consequences for the energy spectrum and temperature anisotropies of the Cosmic Microwave Background (CMB). In this contribution we provide a short historical overview in connection with the cosmological recombination epoch and its connection to the CMB. A...

  12. Algae-based oral recombinant vaccines

    OpenAIRE

    Specht, Elizabeth A.; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for “molecular pharming” in food crops has waned in the last decade due to difficulty in ...

  13. Consequences of recombination on traditional phylogenetic analysis

    DEFF Research Database (Denmark)

    Schierup, M H; Hein, J

    2000-01-01

    We investigate the shape of a phylogenetic tree reconstructed from sequences evolving under the coalescent with recombination. The motivation is that evolutionary inferences are often made from phylogenetic trees reconstructed from population data even though recombination may well occur (mtDNA o...... to a large overestimation of the substitution rate heterogeneity and the loss of the molecular clock. These results are discussed in relation to viral and mtDNA data sets. Udgivelsesdato: 2000-Oct...

  14. Recombination rate predicts inversion size in Diptera.

    Science.gov (United States)

    Cáceres, M; Barbadilla, A; Ruiz, A

    1999-09-01

    Most species of the Drosophila genus and other Diptera are polymorphic for paracentric inversions. A common observation is that successful inversions are of intermediate size. We test here the hypothesis that the selected property is the recombination length of inversions, not their physical length. If so, physical length of successful inversions should be negatively correlated with recombination rate across species. This prediction was tested by a comprehensive statistical analysis of inversion size and recombination map length in 12 Diptera species for which appropriate data are available. We found that (1) there is a wide variation in recombination map length among species; (2) physical length of successful inversions varies greatly among species and is inversely correlated with the species recombination map length; and (3) neither the among-species variation in inversion length nor the correlation are observed in unsuccessful inversions. The clear differences between successful and unsuccessful inversions point to natural selection as the most likely explanation for our results. Presumably the selective advantage of an inversion increases with its length, but so does its detrimental effect on fertility due to double crossovers. Our analysis provides the strongest and most extensive evidence in favor of the notion that the adaptive value of inversions stems from their effect on recombination.

  15. Recombination of U92+ ions with electrons

    International Nuclear Information System (INIS)

    Recombination of fully stripped U92+ ions with electrons has been investigated at the Experimental Storage Ring (ESR) in Darmstadt. Absolute recombination rate coefficients have been measured for relative energies from 0 to 33 eV. For energies greater than 20 meV the experimental result is well described by the theory for radiative recombination (RR). Below 20 meV the experimental rate increasingly exceeds the RR calculation as observed previously in the recombination of light bare ions as well as of Bi83+. This low-energy rate enhancement is shown to scale as Z2.6 for bare ions, where Z is the atomic number of the ion. The U92+ recombination rate enhancement is insensitive to changes of the electron density. Variation of the magnetic guiding field strength from 80 mT to 120 mT resulted in oscillations of the recombination rate at 0 eV. The oscillations are partly attributed to changes of the transverse electron temperature accompanying the change of the magnetic guiding field strength; partly they may be caused by uncompensated small changes of the interaction angle between the two beams. (orig.)

  16. Dissociation of recombinant prion autocatalysis from infectivity.

    Science.gov (United States)

    Noble, Geoffrey P; Supattapone, Surachai

    2015-01-01

    Within the mammalian prion field, the existence of recombinant prion protein (PrP) conformers with self-replicating (ie. autocatalytic) activity in vitro but little to no infectious activity in vivo challenges a key prediction of the protein-only hypothesis of prion replication--that autocatalytic PrP conformers should be infectious. To understand this dissociation of autocatalysis from infectivity, we recently performed a structural and functional comparison between a highly infectious and non-infectious pair of autocatalytic recombinant PrP conformers derived from the same initial prion strain. (1) We identified restricted, C-terminal structural differences between these 2 conformers and provided evidence that these relatively subtle differences prevent the non-infectious conformer from templating the conversion of native PrP(C) substrates containing a glycosylphosphatidylinositol (GPI) anchor. (1) In this article we discuss a model, consistent with these findings, in which recombinant PrP, lacking post-translational modifications and associated folding constraints, is capable of adopting a wide variety of autocatalytic conformations. Only a subset of these recombinant conformers can be adopted by post-translationally modified native PrP(C), and this subset represents the recombinant conformers with high specific infectivity. We examine this model's implications for the generation of highly infectious recombinant prions and the protein-only hypothesis of prion replication.

  17. Antithrombin III for critically ill patients

    DEFF Research Database (Denmark)

    Allingstrup, Mikkel; Wetterslev, Jørn; Ravn, Frederikke B;

    2016-01-01

    , bleeding events, the effect on sepsis and disseminated intravascular coagulation (DIC) and the length of stay in the intensive care unit (ICU) and in hospital in general. SEARCH METHODS: We searched the following databases from inception to 27 August 2015: Cochrane Central Register of Controlled Trials...

  18. Performance testing of passive autocatalytic recombiners (PARs)

    Energy Technology Data Exchange (ETDEWEB)

    Blanchat, T. [Sandia National Laboratories, Albuquerque, NM (United States); Malliakos, A. [U.S. Nuclear Regulatory Commission, Washington, DC (United States)

    1997-03-01

    Passive autocatalytic recombiners (PARs) have been under consideration in the U.S. as a combustible gas control system in advanced light water reactor (ALWR) containments for design basis and severe accidents. PARs do not require a source of power. Instead they use palladium or platinum as a catalyst to recombine hydrogen and oxygen gases into water vapor upon contact with the catalyst. Energy from the recombination of hydrogen with oxygen is released at a relatively slow but continuous rate into the containment which prevents the pressure from becoming too high. The heat produced creates strong buoyancy effects which increases the influx of the surrounding gases to the recombiner. These natural convective flow currents promote mixing of combustible gases in the containment. PARs are self-starting and self-feeding under a very wide range of conditions. The recombination rate of the PAR system needs to be great enough to keep the concentration of hydrogen (or oxygen) below acceptable limits. There are several catalytic recombiner concepts under development worldwide. The USNRC is evaluating a specific design of a PAR which is in an advanced stage of engineering development and has been proposed for ALWR designs. Sandia National laboratories (SNL), under the sponsorship and the direction of the USNRC, is conducting an experimental program to evaluate the performance of PARs. The PAR will be tested at the SURTSEY facility at SNL. The test plan currently includes the following experiments: experiments will be conducted to define the startup characteristics of PARs (i.e., to define what is the lowest hydrogen concentration that the PAR starts recombining the hydrogen with oxygen); experiments will be used to define the hydrogen depletion rate of PARs as a function of hydrogen concentration; and experiments will be used to define the PAR performance in the presence of high concentrations of steam. (author)

  19. Recombination and population structure in Salmonella enterica.

    Directory of Open Access Journals (Sweden)

    Xavier Didelot

    2011-07-01

    Full Text Available Salmonella enterica is a bacterial pathogen that causes enteric fever and gastroenteritis in humans and animals. Although its population structure was long described as clonal, based on high linkage disequilibrium between loci typed by enzyme electrophoresis, recent examination of gene sequences has revealed that recombination plays an important evolutionary role. We sequenced around 10% of the core genome of 114 isolates of enterica using a resequencing microarray. Application of two different analysis methods (Structure and ClonalFrame to our genomic data allowed us to define five clear lineages within S. enterica subspecies enterica, one of which is five times older than the other four and two thirds of the age of the whole subspecies. We show that some of these lineages display more evidence of recombination than others. We also demonstrate that some level of sexual isolation exists between the lineages, so that recombination has occurred predominantly between members of the same lineage. This pattern of recombination is compatible with expectations from the previously described ecological structuring of the enterica population as well as mechanistic barriers to recombination observed in laboratory experiments. In spite of their relatively low level of genetic differentiation, these lineages might therefore represent incipient species.

  20. Graded Recombination Layers for Multijunction Photovoltaics

    KAUST Repository

    Koleilat, Ghada I.

    2012-06-13

    Multijunction devices consist of a stack of semiconductor junctions having bandgaps tuned across a broad spectrum. In solar cells this concept is used to increase the efficiency of photovoltaic harvesting, while light emitters and detectors use it to achieve multicolor and spectrally tunable behavior. In series-connected current-matched multijunction devices, the recombination layers must allow the hole current from one cell to recombine, with high efficiency and low voltage loss, with the electron current from the next cell. We recently reported a tandem solar cell in which the recombination layer was implemented using a progression of n-type oxides whose doping densities and work functions serve to connect, with negligible resistive loss at solar current densities, the constituent cells. Here we present the generalized conditions for design of efficient graded recombination layer solar devices. We report the number of interlayers and the requirements on work function and doping of each interlayer, to bridge an work function difference as high as 1.6 eV. We also find solutions that minimize the doping required of the interlayers in order to minimize optical absorption due to free carriers in the graded recombination layer (GRL). We demonstrate a family of new GRL designs experimentally and highlight the benefits of the progression of dopings and work functions in the interlayers. © 2012 American Chemical Society.

  1. Recombinant expression systems for allergen vaccines.

    Science.gov (United States)

    Singh, Mohan B; Bhalla, Prem L

    2006-01-01

    Allergen immunotherapy of future is likely to be based on allergy vaccines that contain engineered allergens modified to abolish or substantially reduce their IgE-binding activity in order to remove the risk of unwanted anaphylactic responses. The development of efficient systems for the production of recombinant allergens in sufficient quantities is requirement for establishing use of engineered allergens as components of allergy vaccines. This review outlines relative advantages and disadvantages of various heterologous systems for production of recombinant allergens. Microbial systems are most convenient and cost effective platforms for the production of recombinant allergens. However, lack of post-translational processing implies that some allergens have to be expressed in eukaryotic systems for proper folding and post-translational modifications such as glycosylation. Yeast systems can yield high levels of recombinant allergens but often are associated with hyper- glycosylation problems. Mammalian cell culture systems offer suitable post -translational modifications but are nearly hundred fold more expensive than microbial systems. The use of plants as bio-factories for production of recombinant allergens is emerging as a very attractive option as plants-based production system offer several advantages over other expression systems such as post translational processing of proteins, low production costs, scale up ability and enhanced safety due to absence of animal or human pathogens.

  2. Recombinant human erythropoietin in sports: a review

    Directory of Open Access Journals (Sweden)

    Rafael Maia de Almeida Bento

    2003-06-01

    Full Text Available Erythropoietin is an endogenous hormone of glicoproteic nature secreted by the kidneys and is the main regulator of the erythropoiesis. An alteration in its production generates a disturbance in the plasmatic concentration giving rise to several types of pathologies related to the hematopoietic system. The recombinant forms of erythropoietin have indiscriminately been used by athletes, mainly in endurance sports, by increasing the erythrocytes concentration, generating a better delivery of oxygen to the muscle tissue. The administration of recombinant erythropoietin was prohibited by the International Olympic Committee and its use considered as doping. This review has the intention to describe the physical, biological and pharmacokinetic properties of the endogenous erythropoietin, as well as its recombinant form, describing also its use in sports and the process of searching methodologies for its detection in doping control.

  3. Comparison of recombination models in organic bulk heterojunction solar cells

    International Nuclear Information System (INIS)

    Recombination in bulk-heterojunction (BHJ) organic solar cells is the key loss mechanism, and it directly affects characteristic parameters such as power conversion efficiency, short-circuit current, open-circuit voltage, and fill factor. However, which recombination mechanism dominates the loss in organic materials is unclear at present. In this work, we simulate state-of-art BHJ solar cells using five recombination models, including direct recombination, Langevin recombination, charge transfer state recombination, trap-assisted recombination, and recombination via tail. All processes are strongly dependent on charge carrier mobility and exhibit a similar recombination distribution in active layer. For high mobilities, all models present a similar behavior along with the increased mobilities, whereas, there are slight differences in open-circuit voltage between trap/tail model and other ones at lower mobilities, resulting from the interaction between photo-carriers and dark-carriers

  4. Quantum Electrodynamics Theory of Laser Assisted Recombination

    Institute of Scientific and Technical Information of China (English)

    敖淑艳; 程太旺; 李晓峰; 潘守甫; 傅盘铭

    2003-01-01

    Using a formal scattering theoretical approach, we develop a nonperturbative quantum electrodynamics theory to describe laser assisted recombination (LAR), in which an electron initially in the quantized Volkov state recombines with an ion and emits a high-energy photon with frequency defined by energy conservation laws.The transition probability is expressed as an analytic closed form and the spectrum of LAR reflects mainly the properties of general Bessel functions. For the case of a fast electron the LAR spectrum is confined in a well-defined range, while for a slow electron, the LAR spectrum exhibits a double-plateau structure.

  5. Probabilistic divergence measures for detecting interspecies recombination.

    Science.gov (United States)

    Husmeier, D; Wright, F

    2001-01-01

    This paper proposes a graphical method for detecting interspecies recombination in multiple alignments of DNA sequences. A fixed-size window is moved along a given DNA sequence alignment. For every position, the marginal posterior probability over tree topologies is determined by means of a Markov chain Monte Carlo simulation. Two probabilistic divergence measures are plotted along the alignment, and are used to identify recombinant regions. The method is compared with established detection methods on a set of synthetic benchmark sequences and two real-world DNA sequence alignments.

  6. Thermal Recombination: Beyond the Valence Quark Approximation

    CERN Document Server

    Müller, B; Bass, S A

    2005-01-01

    Quark counting rules derived from recombination models agree well with data on hadron production at intermediate transverse momenta in relativistic heavy-ion collisions. They convey a simple picture of hadrons consisting only of valence quarks. We discuss the inclusion of higher Fock states that add sea quarks and gluons to the hadron structure. We show that, when recombination occurs from a thermal medium, hadron spectra remain unaffected by the inclusion of higher Fock states. However, the quark number scaling for elliptic flow is somewhat affected. We discuss the implications for our understanding of data from the Relativistic Heavy Ion Collider.

  7. SIR epidemics in monogamous populations with recombination

    CERN Document Server

    Zanette, Damián H

    2011-01-01

    We study the propagation of an SIR (susceptible-infectious-recovered) disease over an agent population which, at any instant, is fully divided into couples of agents. Couples are occasionally allowed to exchange their members. This process of couple recombination can compensate the instantaneous disconnection of the interaction pattern and thus allow for the propagation of the infection. We study the incidence of the disease as a function of its infectivity and of the recombination rate of couples, thus characterizing the interplay between the epidemic dynamics and the evolution of the population's interaction pattern.

  8. A study on the relationship between gene polymorphisms of Antithrombin Ⅲ and Factor V and preeclampsia and eclampsia in the Han nationality women of Guangdong, China%广东籍汉族妇女抗凝血酶Ⅲ和Factor V基因多态性与子痫前期和子痫的相关性研究

    Institute of Scientific and Technical Information of China (English)

    苏念军; 李冰; 冯建怀; 于滨

    2011-01-01

    Objective To investigate a potential association of the gene polymorphisms of antithrombin m and Factor V gene with preeclampsia and eclampsia in the Han nationality women of Guangdong,China. Methods The antithrombin Ⅱ gene polymorphisms and Factor V gene Leiden mutation in 54 pregnancy women with preeclampsia and eclampsia (observation group) and 513 normal pregnancy women (control group) were analyzed retrospectively. The polymorphisms were determined by DdeI and Mnll restriction enzyme PCR-RFLP, respectively. Results The frequency of Antithrombin Ⅲ DdeI++, DdeI+-and Ddel-genotypes in observation group was 51.9% ,27.8% and 20.4% ,respectively,while in the control group,the frequency was 66.7 %, 25.5% and 7.8%, respectively. The frequencies of DdeI-genotype in observation group were significantly higher than those in the control group (34.3% ,20.6% ,P<0.01 ). Furthermore, the risk rate of this genotype was 3.025. Factor V gene Leiden mutation was not detected in both observation group and control group patients. Conclusion Antithrombin Ⅲ gene polymorphisms might be a high risk factor of preeclaropsia and eclampsia in Guangdong Hah nationality women.However,Factor V Leiden mutation might not be a high risk factor of preeclampsia and eclampsia in Guangdong Han nationality women.%目的 探讨抗凝血酶III(AT-Ⅲ),凝血因子V (Factor V)基因多态性与广东籍汉族早孕期妇女子痫前期和子痫发生的关系.方法 回顾性分析567例早孕期广东籍汉族妇女AT-Ⅲ及Factor V基因的突变情况,将其中54例妊娠20周后发生子痫前期和子痫的患者作为观察组,513例正常妊娠者作为对照组.基因突变检测分别采用DdeI和MnlI限制性内切酶片段长度多态性分析.结果 观察组AT Ⅲ DdeI++、Ddel+-及DdeI--基因型频率分别为51.9%、27.8%和20.4%,对照组则分别为66.7%,25.5%和7.8%.观察组AT Ⅲ Ddel-基因型频率显著高于对照组(34.3%,20.6%,P<0.01),AT Ⅲ Ddel--

  9. Recombinant microorganisms for increased production of organic acids

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Jian; Kleff, Susanne; Guettler, Michael V

    2013-04-30

    Disclosed are recombinant microorganisms for producing organic acids. The recombinant microorganisms express a polypeptide that has the enzymatic activity of an enzyme that is utilized in the pentose phosphate cycle. The recombinant microorganism may include recombinant Actinobacillus succinogenes that has been transformed to express a Zwischenferment (Zwf) gene. The recombinant microorganisms may be useful in fermentation processes for producing organic acids such as succinic acid and lactic acid. Also disclosed are novel plasmids that are useful for transforming microorganisms to produce recombinant microorganisms that express enzymes such as Zwf.

  10. V(D)J recombination frequency is affected by the sequence interposed between a pair of recombination signals: sequence comparison reveals a putative recombinational enhancer element

    DEFF Research Database (Denmark)

    Roch, F A; Hobi, R; Berchtold, M W;

    1997-01-01

    The immunoglobulin heavy chain intron enhancer (Emu) not only stimulates transcription but also V(D)J recombination of chromosomally integrated recombination substrates. We aimed at reproducing this effect in recombination competent cells by transient transfection of extrachromosomal substrates...... respectively, can markedly affect the frequency of V(D)J recombination. We report that the entire Emu, the Emu core as well as its flanking 5' and 3' matrix associated regions (5' and 3' MARs) upregulate V(D)J recombination while the downstream section of the 3' MAR of Emu does not. Also, prokaryotic sequences...

  11. Recombinant protein blends: silk beyond natural design.

    Science.gov (United States)

    Dinjaski, Nina; Kaplan, David L

    2016-06-01

    Recombinant DNA technology and new material concepts are shaping future directions in biomaterial science for the design and production of the next-generation biomaterial platforms. Aside from conventionally used synthetic polymers, numerous natural biopolymers (e.g., silk, elastin, collagen, gelatin, alginate, cellulose, keratin, chitin, polyhydroxyalkanoates) have been investigated for properties and manipulation via bioengineering. Genetic engineering provides a path to increase structural and functional complexity of these biopolymers, and thereby expand the catalog of available biomaterials beyond that which exists in nature. In addition, the integration of experimental approaches with computational modeling to analyze sequence-structure-function relationships is starting to have an impact in the field by establishing predictive frameworks for determining material properties. Herein, we review advances in recombinant DNA-mediated protein production and functionalization approaches, with a focus on hybrids or combinations of proteins; recombinant protein blends or 'recombinamers'. We highlight the potential biomedical applications of fibrous protein recombinamers, such as Silk-Elastin Like Polypeptides (SELPs) and Silk-Bacterial Collagens (SBCs). We also discuss the possibility for the rationale design of fibrous proteins to build smart, stimuli-responsive biomaterials for diverse applications. We underline current limitations with production systems for these proteins and discuss the main trends in systems/synthetic biology that may improve recombinant fibrous protein design and production.

  12. Algae-based oral recombinant vaccines.

    Science.gov (United States)

    Specht, Elizabeth A; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for "molecular pharming" in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered - from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity. PMID:24596570

  13. Genetic Recombination as a Chemical Reaction Network

    OpenAIRE

    Müller, Stefan; Hofbauer, Josef

    2015-01-01

    The process of genetic recombination can be seen as a chemical reaction network with mass-action kinetics. We review the known results on existence, uniqueness, and global stability of an equilibrium in every compatibility class and for all rate constants, from both the population genetics and the reaction networks point of view.

  14. Why do bacteria engage in homologous recombination?

    NARCIS (Netherlands)

    Vos, M.

    2009-01-01

    Microbiologists have long recognized that the uptake and incorporation of homologous DNA from outside the cell is a common feature of bacteria, with important implications for their evolution. However, the exact reasons why bacteria engage in homologous recombination remain elusive. This Opinion art

  15. Evidence for homologous recombination in Chikungunya Virus.

    Science.gov (United States)

    Casal, Pablo E; Chouhy, Diego; Bolatti, Elisa M; Perez, Germán R; Stella, Emma J; Giri, Adriana A

    2015-04-01

    Chikungunya Virus (CHIKV), a mosquito-transmitted alphavirus, causes acute fever and joint pain in humans. Recently, endemic CHIKV infection outbreaks have jeopardized public health in wider geographical regions. Here, we analyze the phylogenetic associations of CHIKV and explore the potential recombination events on 152 genomic isolates deposited in GenBank database. The CHIKV genotypes [West African, Asian, East/Central/South African (ECSA)], and a clear division of ECSA clade into three sub-groups (I-II-III), were defined by Bayesian analysis; similar results were obtained using E1 gene sequences. A nucleotide identity-based approach is provided to facilitate CHIKV classification within ECSA clade. Using seven methods to detect recombination, we found a statistically significant event (p-values range: 1.14×10(-7)-4.45×10(-24)) located within the nsP3 coding region. This finding was further confirmed by phylogenetic networks (PHI Test, p=0.004) and phylogenetic tree incongruence analysis. The recombinant strain, KJ679578/India/2011 (ECSA III), derives from viruses of ECSA III and ECSA I. Our study demonstrates that recombination is an additional mechanism of genetic diversity in CHIKV that might assist in the cross-species transmission process.

  16. Algae-based oral recombinant vaccines.

    Science.gov (United States)

    Specht, Elizabeth A; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for "molecular pharming" in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered - from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity.

  17. Algae-based oral recombinant vaccines

    Directory of Open Access Journals (Sweden)

    Elizabeth A Specht

    2014-02-01

    Full Text Available Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for molecular pharming in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae are poised to become the next candidate in recombinant subunit vaccine production, and they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally-delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered – from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and system immune reactivity.

  18. Vaccine development using recombinant DNA technology

    Science.gov (United States)

    Vaccines induce an immune response in the host that subsequently recognizes infectious agents and helps fight off the disease; vaccines must do this without causing the disease. This paper reviews the development of recombinant DNA technologies as a means of providing new ways for attenuating diseas...

  19. Selected techniques in recombinant DNA technology

    International Nuclear Information System (INIS)

    Recombined DNA technology comprises a complex of techniques in the fields of nucleic acid biochemistry and molecular biology. This presentation gives an introduction, a brief description and example of the procedures of some of the basic techniques in the DNA cloning work currently used. 8 refs

  20. Recombinant DNA: Scientific and Social Perspectives.

    Science.gov (United States)

    Vandegrift, Vaughn

    1979-01-01

    This article is designed to inform chemical educators not engaged in this technology as to the nature and methods used in the technology, the reasons for scientific and social concern, and the attempts made to assuage concerns involving recombinant DNA research. (author/BB)

  1. Recombinant vaccines: experimental and applied aspects

    DEFF Research Database (Denmark)

    Lorenzen, Niels

    1999-01-01

    Development of vaccines for aquaculture fish represent an important applied functional aspect of fish immunology research. Particularly in the case of recombinant vaccines, where a single antigen is usually expected to induce immunity to a specific pathogen, knowledge of mechanisms involved in in...

  2. Asthma and Therapeutics: Recombinant Therapies in Asthma

    Directory of Open Access Journals (Sweden)

    Cockcroft Donald W

    2005-03-01

    Full Text Available Abstract Numerous recombinant therapies are being investigated for the treatment of asthma. This report reviews the current status of several of these novel agents. Anti-immunoglobulin (IgE (omalizumab, Xolair markedly inhibits all aspects of the allergen challenge in subjects who have reduction of free serum IgE to undetectable levels. Several clinical studies in atopic asthma have demonstrated benefit by improved symptoms and lung function and a reduction in corticosteroid requirements. Early use in atopic asthmatics may be even more effective. Several approaches target interleukin (IL-4. Soluble IL-4 receptor has been shown to effectively replace inhaled corticosteroid; further studies are under way. Recombinant anti-IL-5 and recombinant IL-12 inhibit blood and sputum eosinophils and allergen-induced eosinophilia without any effect on airway responsiveness, allergen-induced airway responses, or allergen-induced airway hyperresponsiveness. Efalizumab, a recombinant antibody that inhibits lymphocyte trafficking, is effective in psoriasis. A bronchoprovocation study showed a reduction in allergen-induced late asthmatic response and allergen-induced eosinophilia, which suggests that it should be effective in clinical asthma. These exciting novel therapies provide not only promise of new therapies for asthma but also valuable tools for investigation of asthma mechanisms.

  3. Recombinant protein blends: silk beyond natural design.

    Science.gov (United States)

    Dinjaski, Nina; Kaplan, David L

    2016-06-01

    Recombinant DNA technology and new material concepts are shaping future directions in biomaterial science for the design and production of the next-generation biomaterial platforms. Aside from conventionally used synthetic polymers, numerous natural biopolymers (e.g., silk, elastin, collagen, gelatin, alginate, cellulose, keratin, chitin, polyhydroxyalkanoates) have been investigated for properties and manipulation via bioengineering. Genetic engineering provides a path to increase structural and functional complexity of these biopolymers, and thereby expand the catalog of available biomaterials beyond that which exists in nature. In addition, the integration of experimental approaches with computational modeling to analyze sequence-structure-function relationships is starting to have an impact in the field by establishing predictive frameworks for determining material properties. Herein, we review advances in recombinant DNA-mediated protein production and functionalization approaches, with a focus on hybrids or combinations of proteins; recombinant protein blends or 'recombinamers'. We highlight the potential biomedical applications of fibrous protein recombinamers, such as Silk-Elastin Like Polypeptides (SELPs) and Silk-Bacterial Collagens (SBCs). We also discuss the possibility for the rationale design of fibrous proteins to build smart, stimuli-responsive biomaterials for diverse applications. We underline current limitations with production systems for these proteins and discuss the main trends in systems/synthetic biology that may improve recombinant fibrous protein design and production. PMID:26686863

  4. CATALYTIC RECOMBINER FOR A NUCLEAR REACTOR

    Science.gov (United States)

    King, L.D.P.

    1960-07-01

    A hydrogen-oxygen recombiner is described for use with water-boiler type reactors. The catalyst used is the wellknown platinized alumina, and the novelty lies in the structural arrangement used to prevent flashback through the gas input system. The recombiner is cylindrical, the gases at the input end being deflected by a baffle plate through a first flashback shield of steel shot into an annular passage adjacent to and extending the full length of the housing. Below the baffle plate the gases flow first through an outer annular array of alumina pellets which serve as a second flashback shield, a means of distributing the flowing gases evenly and as a means of reducing radiation losses to the walls. Thereafter the gases flow inio the centrally disposed catalyst bed where recombination is effected. The steam and uncombined gases flow into a centrally disposed cylindrical passage inside the catalyst bod and thereafter out through the exit port. A high rate of recombination is effected.

  5. Haemostatic effects of recombinant coagulation factor VIIa

    NARCIS (Netherlands)

    Lisman, Johannes Antonius

    2003-01-01

    Recombinant coagulation factor VIIa (rFVIIa) has recently become available for treatment of patients with inhibitor-complicated haemophilia. It has been postulated that rFVIIa could become a universal haemostatic agent. Case reports and small studies confirm efficacy and safety of rFVIIa in a variet

  6. Generation of Modified Pestiviruses by Targeted Recombination

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Bruun; Friis, Martin Barfred; Risager, Peter Christian;

    and hence is not limited to the use of internal restriction sites. Rescue of modified pestiviruses can be obtained by electroporation of cell cultures with full-length RNA transcripts in vitro transcribed from the recombined BAC clones. We have used this approach to generate a series of new pestivirus BACs...

  7. Experimental Mg IX photo recombination rate coefficient

    International Nuclear Information System (INIS)

    The rate coefficient for radiative and dielectronic recombination of beryllium-like magnesium ions was measured with high resolution at the Heidelberg heavy-ion storage ring TSR. In the electron-ion collision energy range 0-207 eV resonances due to 2s → 2p (ΔN = 0) and 2s → 3l (ΔN = 1) core excitations were detected. At low energies below 0.15 eV the recombination rate coefficient is dominated by strong 1s2(2s2p 3P)7l resonances with the strongest one occurring at an energy of only 21 meV. These resonances decisively influence the Mg IX recombination rate coefficient in a low temperature plasma. The experimentally derived Mg IX dielectronic recombination rate coefficient (±15% systematical uncertainty) is compared with the recommendation by Mazzotta et al. (1998, AandAS, 133, 403) and the recent calculations by Gu (2003, ApJ, 590, 1131) and by Colgan et al. (2003, AandA, 412, 597). These results deviate from the experimental rate coefficient by 130%, 82% and 25%, respectively, at the temperature where the fractional abundance of Mg IX is expected to peak in a photoionized plasma. At this temperature a theoretical uncertainty in the 1s2(2s2p 3P)7l resonance positions of only 100 meV would translate into an uncertainty of the plasma rate coefficient of almost a factor 3. This finding emphasizes that an accurate theoretical calculation of the Mg IX recombination rate coefficient from first principles is challenging. (authors)

  8. Branching innovation, recombinant innovation, and endogenous technological transitions

    NARCIS (Netherlands)

    Frenken, K.; Izquierdo, L.; Zeppini, P.

    2012-01-01

    We propose a model of technological transitions based on two different types of innovations. Branching innovations refer to technological improvements along a particular path, while recombinant innovations represent fusions of multiple paths. Recombinant innovations create "short-cuts" which reduce

  9. Caenorhabditis briggsae recombinant inbred line genotypes reveal inter-strain incompatibility and the evolution of recombination.

    Directory of Open Access Journals (Sweden)

    Joseph A Ross

    2011-07-01

    Full Text Available The nematode Caenorhabditis briggsae is an emerging model organism that allows evolutionary comparisons with C. elegans and exploration of its own unique biological attributes. To produce a high-resolution C. briggsae recombination map, recombinant inbred lines were generated from reciprocal crosses between two strains and genotyped at over 1,000 loci. A second set of recombinant inbred lines involving a third strain was also genotyped at lower resolution. The resulting recombination maps exhibit discrete domains of high and low recombination, as in C. elegans, indicating these are a general feature of Caenorhabditis species. The proportion of a chromosome's physical size occupied by the central, low-recombination domain is highly correlated between species. However, the C. briggsae intra-species comparison reveals striking variation in the distribution of recombination between domains. Hybrid lines made with the more divergent pair of strains also exhibit pervasive marker transmission ratio distortion, evidence of selection acting on hybrid genotypes. The strongest effect, on chromosome III, is explained by a developmental delay phenotype exhibited by some hybrid F2 animals. In addition, on chromosomes IV and V, cross direction-specific biases towards one parental genotype suggest the existence of cytonuclear epistatic interactions. These interactions are discussed in relation to surprising mitochondrial genome polymorphism in C. briggsae, evidence that the two strains diverged in allopatry, the potential for local adaptation, and the evolution of Dobzhansky-Muller incompatibilities. The genetic and genomic resources resulting from this work will support future efforts to understand inter-strain divergence as well as facilitate studies of gene function, natural variation, and the evolution of recombination in Caenorhabditis nematodes.

  10. Mechanisms and factors that influence high frequency retroviral recombination

    DEFF Research Database (Denmark)

    Delviks-Frankenberry, Krista; Galli, Andrea; Nikolaitchik, Olga;

    2011-01-01

    With constantly changing environmental selection pressures, retroviruses rely upon recombination to reassort polymorphisms in their genomes and increase genetic diversity, which improves the chances for the survival of their population. Recombination occurs during DNA synthesis, whereby reverse...... transcriptase undergoes template switching events between the two copackaged RNAs, resulting in a viral recombinant with portions of the genetic information from each parental RNA. This review summarizes our current understanding of the factors and mechanisms influencing retroviral recombination, fidelity......, and vaccine development....

  11. Hyper-Recombining Recipient Strains in Bacterial Conjugation

    OpenAIRE

    Feinstein, Sheldon I.; Low, K. Brooks

    1986-01-01

    Using a direct enrichment and screening procedure, mutants of Escherichia coli have been isolated in which recombination frequencies for several intragenic Hfr x F- crosses are significantly higher (twofold to sixfold) than in the parental strains. These hyper-recombination mutations comprised five new mutS- and one new mutL- allele. Together with other known mut - alleles, they were analyzed for effects on intragenic recombination using several types of crosses. Hyper-recombination was fou...

  12. Orientation-dependent perimeter recombination in GaAs diodes

    Energy Technology Data Exchange (ETDEWEB)

    Stellwag, T.B.; Melloch, M.R.; Lundstrom, M.S.; Carpenter, M.S.; Pierret, R.F. (School of Electrical Engineering, Purdue University, West Lafayette, Indiana 47907 (USA))

    1990-04-23

    Perimeter recombination currents affect the performance of GaAs-based devices such as solar cells, heterojunction bipolar transistors, and injection lasers. We report that the {ital n}{congruent}2 perimeter recombination current has a strong orientation dependence. More than a factor of five variation in the surface recombination current at mesa-etched edges has been observed. These results suggest that with proper device design, perimeter recombination currents could be substantially reduced.

  13. Orientation-dependent perimeter recombination in GaAs diodes

    Science.gov (United States)

    Stellwag, T. B.; Melloch, M. R.; Lundstrom, M. S.; Carpenter, M. S.; Pierret, R. F.

    1990-04-01

    Perimeter recombination currents affect the performance of GaAs-based devices such as solar cells, heterojunction bipolar transistors, and injection lasers. We report that the n≂2 perimeter recombination current has a strong orientation dependence. More than a factor of five variation in the surface recombination current at mesa-etched edges has been observed. These results suggest that with proper device design, perimeter recombination currents could be substantially reduced.

  14. Ion-ion recombination at high ion density

    International Nuclear Information System (INIS)

    By appeal to a Thomson-style treatment of recombination, it is shown that the rate for recombination of ions generated with uniform frequency within a reaction volume is a factor of 9/4 times greater than the rate for recombination of ions which approach each other from infinite separation. A valuable relationship connecting the two problems is uncovered. The analysis is pertinent to recombination involving dilute and high degrees of ionisation. (author)

  15. The functional study of antithrombin L99 mutation%抗凝血酶L99氨基酸位点突变对其功能的影响

    Institute of Scientific and Technical Information of China (English)

    郁婷婷; 戴菁; 丁秋兰; 傅启华; 王学锋

    2014-01-01

    Objective To study the molecular mechanisms of inherited antithrombin (AT)defiency caused by AT L99 mutation.Methods Wild type (WT),L99V,L99A,L99I and L99S AT were purified from drosophila expression system.The binding capacity of AT and the low molecular weight heparin sodium was analyzed by the heparin binding assay.Surface plasmon resonance (SPR) was used to detect the binding ability of AT to thrombin (F Ⅱ a) or AT to coagulation factor X a (F X a).The activity of AT (AT∶ A) was detected by chromogenic assay.Results The purified WT and mutant AT were at the same size.No additional band was observed by coomassie blue staining and western blot assay.Compared to the WT AT,the binding abilities of the low molecular weight heparin sodium to the AT L99V,L99A,L99I and L99S were (44.8±3.6)%,(118.9±14.0)%,(15.2±8.8)%,and (23.0±8.2)%,respectively.The binding abilities of F Ⅱ a to AT L99V,L99A,L99I and L99S were 13%,57%,3%,and 29%,while the binding of F X a to AT L99V,L99A,L99I and L99S were 7%,51%,1%,and 25%.The AT∶A of WT,L99V,L99A,L99I and L99S AT were 146.5%,21.4%,120.9%,10.8%,and 39.0%,respectively.Conclusion The binding abilities of AT to heparin,F Ⅱ a and F X a were damaged by the L99 mutation,which resulted in decreased AT∶ A and inherited AT deficiency.%目的 研究抗凝血酶(AT)L99氨基酸位点突变导致遗传性AT缺陷症的分子机制.方法 利用果蝇细胞表达系统表达纯化野生型AT以及L99V、L99A、L99I和L99S等突变型AT蛋白;采用肝素结合实验检测重组AT蛋白与低分子量肝素钠的结合能力;采用表面等离子共振(SPR)技术检测重组AT蛋白与凝血酶(FⅡa)及活化凝血因子X(FXa)的结合能力;将野生型及各突变型AT蛋白的浓度调整至正常AT血浆浓度后,采用发色底物法检测重组AT蛋白活性.结果 考马斯亮蓝染色及免疫印迹法显示各突变蛋白与野生型AT蛋白大小一致,未见明显杂带.

  16. Replication, recombination, and repair: going for the gold.

    Science.gov (United States)

    Klein, Hannah L; Kreuzer, Kenneth N

    2002-03-01

    DNA recombination is now appreciated to be integral to DNA replication and cell survival. Recombination allows replication to successfully maneuver through the roadblocks of damaged or collapsed replication forks. The signals and controls that permit cells to transition between replication and recombination modes are now being identified.

  17. The unconventional xer recombination machinery of Streptococci/Lactococci

    NARCIS (Netherlands)

    Le Bourgeois, Pascal; Bugarel, Marie; Campo, Nathalie; Daveran-Mingot, Marie-Line; Labonte, Jessica; Lanfranchi, Daniel; Lautier, Thomas; Pages, Carine; Ritzenthaler, Paul

    2007-01-01

    Homologous recombination between circular sister chromosomes during DNA replication in bacteria can generate chromosome dimers that must be resolved into monomers prior to cell division. In Escherichia coli, dimer resolution is achieved by site-specific recombination, Xer recombination, involving tw

  18. Regulation of homologous recombination at telomeres in budding yeast

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine; Lisby, Michael

    2010-01-01

    Homologous recombination is suppressed at normal length telomere sequences. In contrast, telomere recombination is allowed when telomeres erode in the absence of telomerase activity or as a consequence of nucleolytic degradation or incomplete replication. Here, we review the mechanisms...... that contribute to regulating mitotic homologous recombination at telomeres and the role of these mechanisms in signalling short telomeres in the budding yeast Saccharomyces cerevisiae....

  19. Plasmid-to-plasmid recombination in Haemophilus influenzae

    Energy Technology Data Exchange (ETDEWEB)

    Balganesh, M.; Setlow, J.K.

    1986-01-01

    No recombination between plasmids was observed after conjugal transfer of a plasmid into a cell carrying another plasmid. Two types of such recombination took place after transformation, one type being Rec/sup +/ dependent and suggesting a preferred site of recombination. The other much rarer type was at least partially Rec/sup +/ independent.

  20. Mechanism and control of interspecies recombination in Escherichia coli. I. Mismatch repair, methylation, recombination and replication functions.

    OpenAIRE

    Stambuk, S; Radman, M

    1998-01-01

    A genetic analysis of interspecies recombination in Escherichia coli between the linear Hfr DNA from Salmonella typhimurium and the circular recipient chromosome reveals some fundamental aspects of recombination between related DNA sequences. The MutS and MutL mismatch binding proteins edit (prevent) homeologous recombination between these 16% diverged genomes by at least two distinct mechanisms. One is MutH independent and presumably acts by aborting the initiated recombination through the U...

  1. CFD Analysis of Passive Autocatalytic Recombiner

    Directory of Open Access Journals (Sweden)

    B. Gera

    2011-01-01

    Full Text Available In water-cooled nuclear power reactors, significant quantities of hydrogen could be produced following a postulated loss-of-coolant accident (LOCA along with nonavailability of emergency core cooling system (ECCS. Passive autocatalytic recombiners (PAR are implemented in the containment of water-cooled power reactors to mitigate the risk of hydrogen combustion. In the presence of hydrogen with available oxygen, a catalytic reaction occurs spontaneously at the catalyst surfaces below conventional ignition concentration limits and temperature and even in presence of steam. Heat of reaction produces natural convection flow through the enclosure and promotes mixing in the containment. For the assessment of the PAR performance in terms of maximum temperature of catalyst surface and outlet hydrogen concentration an in-house 3D CFD model has been developed. The code has been used to study the mechanism of catalytic recombination and has been tested for two literature-quoted experiments.

  2. Hα diagnostic in a recombining plasma

    Science.gov (United States)

    Wenzel, U.; Goto, M.

    2016-05-01

    In fusion devices the hydrogen Balmer lines are used to measure the neutral flux from the walls into the plasma using the atomic physics factor S/XB. This is a standard diagnostic which can be applied in ionizing plasma using {{H}α} , {{H}β} or {{H}γ} without knowledge of the electron density. We will extend this method to a recombining plasma in front of a surface. {{H}α} can be used in an analogous way to measure the plasma flow to this surface which can be e.g. a divertor target. The other Balmer lines are not suitable because the corresponding atomic physics factor R/YB depends on density due to three-body recombination. An application of this diagnostic method is provided.

  3. Recombination energy in double white dwarf formation

    CERN Document Server

    Nandez, Jose L A; Lombardi, James C

    2015-01-01

    In this Letter we investigate the role of recombination energy during a common envelope event. We confirm that taking this energy into account helps to avoid the formation of the circumbinary envelope commonly found in previous studies. For the first time, we can model a complete common envelope event, with a clean compact double white dwarf binary system formed at the end. The resulting binary orbit is almost perfectly circular. In addition to considering recombination energy, we also show that between 1/4 and 1/2 of the released orbital energy is taken away by the ejected material. We apply this new method to the case of the double-white dwarf system WD 1101+364, and we find that the progenitor system at the start of the common envelope event consisted of a $\\sim1.5M_\\odot$ red giant star in a $\\sim 30$ day orbit with a white dwarf companion.

  4. Classification of Recombinant Biologics in the EU

    DEFF Research Database (Denmark)

    Klein, Kevin; De Bruin, Marie L; Broekmans, Andre W;

    2015-01-01

    before the data is aggregated at the European Union (EU) level, it is important that an unambiguous understanding of which medicinal products belong to the biological product category exists. This study aimed to identify the level of consistency between Member States regarding the classification...... to which products were classified as biologics by each Member State. We calculated the Fleiss kappa value to analyze interrater reliability. RESULTS: A considerable divergence was identified regarding the classification of the 146 recombinant biologics from the sample list: one Member State classified 100...... % of the recombinant biologics from the sample list as biologics, whereas the classification rates in the remaining four Member States ranged between 70 and 88 % for products available on the national market. The interrater reliability for 87 products available on the market in all five Member States was considered...

  5. Charge exchange recombination x-ray laser

    International Nuclear Information System (INIS)

    A recombining plasma x-ray laser using charge exchange recombination (CXR) is proposed. Fully stripped carbon ions collide with neutral He atoms and become excited hydrogenlike carbon ions, in which the excited levels with n=3 or 4 are mainly populated. We calculate the gain coefficients of the Balmer α and the Lyman β line of the hydrogenlike carbon ions by the use of a collisional-radiative model in which the CXR process is included. The calculated result shows that substantial gain can be generated for the Lyman β and Balmer α lines and that the gain of the Balmer α line can be strongly enhanced by the effect of CXR. We also report a preliminary experiment of this scheme. (author)

  6. Recombinant laccase: I. Enzyme cloning and characterization.

    Science.gov (United States)

    Nicolini, Claudio; Bruzzese, Debora; Cambria, Maria Teresa; Bragazzi, Nicola Luigi; Pechkova, Eugenia

    2013-03-01

    We obtained structural and functional characterization of a recombinant Laccase from Rigidoporus lignosus (formerly Rigidoporus microporus), a white-rot basidiomycete, by means of circular dichroism (CD) spectra, cyclic voltammetry (CV) and biochemical assays. Here we report the optimization of expression and purification procedures of a recombinant Laccase expressed in supercompetent Escherichia coli cells. We amplified the coding sequence of Laccase using PCR from cDNA and cloned into a bacterial expression system. The resulting expression plasmid, pET-28b, was under a strong T7/Lac promoter induced by IPTG (isopropyl-β-d-thiogalactoipyranoside). We obtained purification by fast protein liquid chromatography (FPLC) method. We recorded the variation of the current of a solution containing purified Laccase with increasing Syringaldazine (SGZ) concentration using a potentiometer as proof of principle, showing its compatibility with the development of a new enzymatic biosensor for medical purposes, as described in Part II. PMID:22991171

  7. Bacterial Artificial Chromosome Mutagenesis Using Recombineering

    Directory of Open Access Journals (Sweden)

    Kumaran Narayanan

    2011-01-01

    Full Text Available Gene expression from bacterial artificial chromosome (BAC clones has been demonstrated to facilitate physiologically relevant levels compared to viral and nonviral cDNA vectors. BACs are large enough to transfer intact genes in their native chromosomal setting together with flanking regulatory elements to provide all the signals for correct spatiotemporal gene expression. Until recently, the use of BACs for functional studies has been limited because their large size has inherently presented a major obstacle for introducing modifications using conventional genetic engineering strategies. The development of in vivo homologous recombination strategies based on recombineering in E. coli has helped resolve this problem by enabling facile engineering of high molecular weight BAC DNA without dependence on suitably placed restriction enzymes or cloning steps. These techniques have considerably expanded the possibilities for studying functional genetics using BACs in vitro and in vivo.

  8. Radiative transfer effects in primordial hydrogen recombination

    CERN Document Server

    Ali-Haïmoud, Yacine; Hirata, Christopher M

    2010-01-01

    The calculation of a highly accurate cosmological recombination history has been the object of particular attention recently, as it constitutes the major theoretical uncertainty when predicting the angular power spectrum of Cosmic Microwave Background anisotropies. Lyman transitions, in particular the Lyman-alpha line, have long been recognized as one of the bottlenecks of recombination, due to their very low escape probabilities. The Sobolev approximation does not describe radiative transfer in the vicinity of Lyman lines to a sufficient degree of accuracy, and several corrections have already been computed in other works. In this paper, the impact of some previously ignored radiative transfer effects is calculated. First, the effect of Thomson scattering in the vicinity of the Lyman-alpha line is evaluated, using a full redistribution kernel incorporated into a radiative transfer code. The effect of feedback of distortions generated by the optically thick deuterium Lyman-alpha line blueward of the hydrogen ...

  9. Recombinant human erythropoietin in sports: a review

    OpenAIRE

    Rafael Maia de Almeida Bento; Lúcia Menezes Pinto Damasceno; Francisco Radler Aquino Neto

    2003-01-01

    Erythropoietin is an endogenous hormone of glicoproteic nature secreted by the kidneys and is the main regulator of the erythropoiesis. An alteration in its production generates a disturbance in the plasmatic concentration giving rise to several types of pathologies related to the hematopoietic system. The recombinant forms of erythropoietin have indiscriminately been used by athletes, mainly in endurance sports, by increasing the erythrocytes concentration, generating a better delivery of ox...

  10. Recombinant CBM-fusion technology : applications overview

    OpenAIRE

    Oliveira, Carla Cristina Marques de; Carvalho, Vera; Domingues, Lucília; Gama, F. M.

    2015-01-01

    Carbohydrate-binding modules (CBMs) are small components of several enzymes, which present an independent fold and function, and specific carbohydrate-binding activity. Their major function is to bind the enzyme to the substrate enhancing its catalytic activity, especially in the case of insoluble substrates. The immense diversity of CBMs, together with their unique properties, has long raised their attention for many biotechnological applications. Recombinant DNA technology has been used for...

  11. Asthma and Therapeutics: Recombinant Therapies in Asthma

    OpenAIRE

    Cockcroft Donald W

    2005-01-01

    Abstract Numerous recombinant therapies are being investigated for the treatment of asthma. This report reviews the current status of several of these novel agents. Anti-immunoglobulin (Ig)E (omalizumab, Xolair) markedly inhibits all aspects of the allergen challenge in subjects who have reduction of free serum IgE to undetectable levels. Several clinical studies in atopic asthma have demonstrated benefit by improved symptoms and lung function and a reduction in corticosteroid requirements. E...

  12. Quark Recombination in Heavy Ion Collisions

    OpenAIRE

    Fries, Rainer J.(Cyclotron Institute, Department of Physics & Astronomy, Texas A&M University, College Station, TX, 77843-3366, USA)

    2011-01-01

    Data on high energy nuclear collisions collected at the Relativistic Heavy Ion Collider over the past decade have provided convincing evidence that hadronization is quite different in hot nuclear environments compared to p+p collisions. In particular, the data suggest that we see traces of quark degrees of freedom in elliptic flow, with the implication that collective flow is generated on the parton level and is transfered to hadrons through a simple recombination step. In this contribution w...

  13. Virus Strain Discrimination Using Recombinant Antibodies

    OpenAIRE

    Boonham, N.; Barker, I.

    2002-01-01

    Most routine testing for plant viruses is currently carried out using monoclonal and polyclonal antibodies. Traditional methods of antibody production however can be time consuming and require the use of expensive cell culture facilities. Recombinant antibody technology however is starting to make an impact in this area, enabling the selection of antibody fragments in a few weeks compared with the many months associated with traditional methods and requires only basic microbiological faciliti...

  14. Production of recombinant antibodies using bacteriophages

    OpenAIRE

    Shukra, A. M.; Sridevi, N. V.; Dev Chandran,; Kapil Maithal,

    2014-01-01

    Recombinant antibody fragments such as Fab, scFv, diabodies, triabodies, single domain antibodies and minibodies have recently emerged as potential alternatives to monoclonal antibodies, which can be engineered using phage display technology. These antibodies match the strengths of conventionally produced monoclonal antibodies and offer advantages for the development of immunodiagnostic kits and assays. These fragments not only retain the specificity of the whole monoclonal ...

  15. Dielectronic Recombination Rates In Astrophysical Plasmas

    CERN Document Server

    Bachari, F; Maero, G; Quarati, P; Bachari, Fatima; Ferro, Fabrizio; Maero, Giancarlo; Quarati, Piero

    2006-01-01

    In this work we introduce a new expression of the plasma Dielecronic Recombination (DR) rate as a function of the temperature, derived assuming a small deformation of the Maxwell-Boltzmann distribution and containing corrective factors, in addition to the usual exponential behaviour, caused by non-linear effects in slightly non ideal plasmas. We then compare the calculated DR rates with the experimental DR fits in the low temperature region.

  16. Recombination-assisted megaprimer (RAM) cloning

    OpenAIRE

    Jacques Mathieu; Emilia Alvarez; Alvarez, Pedro J. J.

    2014-01-01

    No molecular cloning technique is considered universally reliable, and many suffer from being too laborious, complex, or expensive. Restriction-free cloning is among the simplest, most rapid, and cost-effective methods, but does not always provide successful results. We modified this method to enhance its success rate through the use of exponential amplification coupled with homologous end-joining. This new method, recombination-assisted megaprimer (RAM) cloning, significantly extends the app...

  17. Use of Helical Transport Channels for Bunch Recombination

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David; Yonehara, Katsuya; /Fermilab; Yoshikawa, Cary; /MUONS Inc., Batavia

    2010-03-01

    Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this report we note that the tunable chronicity property of a helical transport channel (HTC) makes it a desirable component of a bunch recombiner. A large chronicity HTC is desirable for the bunch recombining transport, while more isochronous transport may be preferred for rf manipulations. Scenarios for bunch recombination are presented, with initial 1-D simulations, in order to set the stage for future 3-D simulation and optimization. HTC transports may enable a very compact bunch recombiner.

  18. Use of Helical Transport Channels for Bunch Recombination

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David; Yonehara, Katsuya; /Fermilab; Ankenbrandt, C.; Yoshikawa, Cary; /MUONS Inc., Batavia

    2012-05-01

    Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this report we note that the tunable chronicity property of a helical transport channel (HTC) makes it a desirable component of a bunch recombiner. A large chronicity HTC is desirable for the bunch recombining transport, while more isochronous transport may be preferred for rf manipulations. Scenarios for bunch recombination are presented, with initial 1-D simulations, in order to set the stage for future 3-D simulation and optimization. HTC transports may enable a very compact bunch recombiner.

  19. Radiative transfer effects during primordial helium recombination

    CERN Document Server

    Chluba, Jens; Switzer, Eric R

    2011-01-01

    In this paper we refine the calculation of primordial helium recombination, accounting for several additional effects that were neglected or treated more approximately in previous studies. These include consideration of (i) time-dependent radiative transfer interaction between the 2^1 P_1 - 1^1 S_0 and 2^3 P_1 - 1^1 S_0 resonances; (ii) time-dependent radiative transfer for the partially overlapping n^1 P_1 - 1^1 S_0, n^1 D_2 - 1^1 S_0 and n^3 P_1 - 1^1 S_0 series with 3 \\leq n \\leq 10; (iii) electron scattering within a kernel approach. We also briefly discuss the effect of electron scattering and HI quadrupole lines on the recombination of hydrogen. Although the physics of all the considered processes is interesting and subtle, for the standard cosmology the overall correction to the ionization history during helium recombination with respect to the previous treatment remains smaller than |DeltaNe/Ne| \\sim 0.05%. For models with a large helium fraction Y_p \\sim 0.4, the difference can reach |\\DeltaNe/Ne| \\s...

  20. Dissociative recombination of small molecular ions

    International Nuclear Information System (INIS)

    In this thesis an analysis is given of merged electron-ion beam experiment and work on dissociative recombination of molecular ions and electrons is described. Chapter II covers a brief introduction of the theory of dissociative recombination. In chapter III, a description is given of the merged electron-ion beam experiment and a method is described which allows the determination of the mean angle between the electron and ion trajectories in a merged electron-ion beam experiment. In chapter IV a paper on the three dominant atmospheric diatomic ions NO+, O2+ and N2+ is presented and in chapter V the dissociative recombination for N2H+ and N2D+ is discussed. In chapter VI two papers on the polyatomic ions of the carbon-containing molecular ions are presented, and in chapter VII a letter with some results of the work presented in more detail in the chapters IV, V and VI is presented. The magnitude and the energy dependence of the cross-section measured by the merged beam technique and by other techniques is compared and discussed. (Auth.)

  1. CFD modeling of passive autocatalytic recombiners*

    Directory of Open Access Journals (Sweden)

    Orszulik Magdalena

    2015-06-01

    Full Text Available This study deals with numerical modeling of passive autocatalytic hydrogen recombiners (PARs. Such devices are installed within containments of many nuclear reactors in order to remove hydrogen and convert it to steam. The main purpose of this work is to develop a numerical model of passive autocatalytic recombiner (PAR using the commercial computational fluid dynamics (CFD software ANSYS-FLUENT and tuning the model using experimental results. The REKO 3 experiment was used for this purpose. Experiment was made in the Institute for Safety Research and Reactor Technology in Julich (Germany. It has been performed for different hydrogen concentrations, different flow rates, the presence of steam, and different initial temperatures of the inlet mixture. The model of this experimental recombiner was elaborated within the framework of this work. The influence of mesh, gas thermal conductivity coefficient, mass diffusivity coefficients, and turbulence model was investigated. The best results with a good agreement with REKO 3 data were received for k-ɛ model of turbulence, gas thermal conductivity dependent on the temperature and mass diffusivity coefficients taken from CHEMKIN program. The validated model of the PAR was next implemented into simple two-dimensional simulations of hydrogen behavior within a subcompartment of a containment building.

  2. Antagonistic experimental coevolution with a parasite increases host recombination frequency

    Directory of Open Access Journals (Sweden)

    Kerstes Niels AG

    2012-02-01

    Full Text Available Abstract Background One of the big remaining challenges in evolutionary biology is to understand the evolution and maintenance of meiotic recombination. As recombination breaks down successful genotypes, it should be selected for only under very limited conditions. Yet, recombination is very common and phylogenetically widespread. The Red Queen Hypothesis is one of the most prominent hypotheses for the adaptive value of recombination and sexual reproduction. The Red Queen Hypothesis predicts an advantage of recombination for hosts that are coevolving with their parasites. We tested predictions of the hypothesis with experimental coevolution using the red flour beetle, Tribolium castaneum, and its microsporidian parasite, Nosema whitei. Results By measuring recombination directly in the individuals under selection, we found that recombination in the host population was increased after 11 generations of coevolution. Detailed insights into genotypic and phenotypic changes occurring during the coevolution experiment furthermore helped us to reconstruct the coevolutionary dynamics that were associated with this increase in recombination frequency. As coevolved lines maintained higher genetic diversity than control lines, and because there was no evidence for heterozygote advantage or for a plastic response of recombination to infection, the observed increase in recombination most likely represented an adaptive host response under Red Queen dynamics. Conclusions This study provides direct, experimental evidence for an increase in recombination frequency under host-parasite coevolution in an obligatory outcrossing species. Combined with earlier results, the Red Queen process is the most likely explanation for this observation.

  3. FASEB Summer Research Conference. Genetic Recombination and Chromosome Rearrangements

    Energy Technology Data Exchange (ETDEWEB)

    Jinks-Robertson, Sue

    2002-02-01

    The 2001 meeting entitled ''Genetic Recombination and Genome Rearrangements'' was held July 21-26 in Snowmass, Colorado. The goal of the meeting was to bring together scientists using diverse approaches to study all aspects of genetic recombination. This goal was achieved by integrating talks covering the genetics, biochemistry and structural biology of homologous recombination, site-specific recombination, and nonhomologous recombination. The format of the meeting consisted of a keynote address on the opening evening, two formal plenary sessions on each of the four full meeting days, a single afternoon workshop consisting of short talks chosen from among submitted abstracts, and afternoon poster sessions on each of the four full meeting days. The eight plenary session were entitled: (1) Recombination Mechanisms, (2) Prokaryotic Recombination, (3) Repair and Recombination, (4) Site-specific Recombination and Transposition, (5) Eukaryotic Recombination I, (6) Genome Rearrangements, (7) Meiosis, and (8) Eukaryotic Recombination II. Each session included a mix of genetic, biochemical and structural talks; talks were limited to 20 minutes, followed by 10 minutes of very lively, general discussion. Much of the data presented in the plenary sessions was unpublished, thus providing attendees with the most up-to-date knowledge of this rapidly-moving field.

  4. Molecular mechanisms of DNA recombination: testing mitotic and meiotic models

    International Nuclear Information System (INIS)

    A hyperhaploid n + 1 strain of Saccharomyces cerevisiae (LBL1) disomic for chromosome VII was employed to isolate hyper-rec and hypo-rec mutations affecting spontaneous mitotic gene conversion and intergenic recombination. The genotype of LBL1 permits simultaneous and independent identification of rec mutations that enhance or diminish gene conversion and those that enhance or diminish intergenic recombination. Five phenotypic groups of rec mutants were isolated following ultraviolet light mutagenesis. Rec mutations that simultaneously abolish or enhance both classes of recombinational events were detected. These results demonstrate that gene conversion and intergenic recombination are under joint genetic control in mitotic cells. Conversion-specific and intergenic recombination-specific rec mutants were also recovered. Their properties indicate that conversion and intergenic recombination are separable pheonomena dependent upon discrete REC genes. The rec mutants isolated in LBL1 provide a method to test molecular models of mitotic and meiotic recombination

  5. The imperfect ancestral recombination graph reconstruction problem: upper bounds for recombination and homoplasy.

    Science.gov (United States)

    Lam, Fumei; Tarpine, Ryan; Istrail, Sorin

    2010-06-01

    One of the central problems in computational biology is the reconstruction of evolutionary histories. While models incorporating recombination and homoplasy have been studied separately, a missing component in the theory is a robust and flexible unifying model which incorporates both of these major biological events shaping genetic diversity. In this article, we introduce the first such unifying model and develop algorithms to find the optimal ancestral recombination graph incorporating recombinations and homoplasy events. The power of our framework is the connection between our formulation and the Directed Steiner Arborescence Problem in combinatorial optimization. We implement linear programming techniques as well as heuristics for the Directed Steiner Arborescence Problem, and use our methods to construct evolutionary histories for both simulated and real data sets. PMID:20583925

  6. Recombinant pinoresinol/lariciresinol reductase, recombinant dirigent protein, and methods of use

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Norman G. (Pullman, WA); Davin, Laurence B. (Pullman, WA); Dinkova-Kostova, Albena T. (Baltimore, MD); Fujita, Masayuki (Kagawa, JP); Gang, David R. (Ann Arbor, MI); Sarkanen, Simo (S. Minneapolis, MN); Ford, Joshua D. (Pullman, WA)

    2001-04-03

    Dirigent proteins and pinoresinol/lariciresinol reductases have been isolated, together with cDNAs encoding dirigent proteins and pinoresinol/lariciresinol reductases. Accordingly, isolated DNA sequences are provided which code for the expression of dirigent proteins and pinoresinol/lariciresinol reductases. In other aspects, replicable recombinant cloning vehicles are provided which code for dirigent proteins or pinoresinol/lariciresinol reductases or for a base sequence sufficiently complementary to at least a portion of dirigent protein or pinoresinol/lariciresinol reductase DNA or RNA to enable hybridization therewith. In yet other aspects, modified host cells are provided that have been transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence encoding dirigent protein or pinoresinol/lariciresinol reductase. Thus, systems and methods are provided for the recombinant expression of dirigent proteins and/or pinoresinol/lariciresinol reductases.

  7. Live-Cell Imaging of Vaccinia Virus Recombination

    Science.gov (United States)

    Paszkowski, Patrick; Noyce, Ryan S.; Evans, David H.

    2016-01-01

    Recombination between co-infecting poxviruses provides an important mechanism for generating the genetic diversity that underpins evolution. However, poxviruses replicate in membrane-bound cytoplasmic structures known as factories or virosomes. These are enclosed structures that could impede DNA mixing between co-infecting viruses, and mixing would seem to be essential for this process. We hypothesize that virosome fusion events would be a prerequisite for recombination between co-infecting poxviruses, and this requirement could delay or limit viral recombination. We have engineered vaccinia virus (VACV) to express overlapping portions of mCherry fluorescent protein fused to a cro DNA-binding element. In cells also expressing an EGFP-cro fusion protein, this permits live tracking of virus DNA and genetic recombination using confocal microscopy. Our studies show that different types of recombination events exhibit different timing patterns, depending upon the relative locations of the recombining elements. Recombination between partly duplicated sequences is detected soon after post-replicative genes are expressed, as long as the reporter gene sequences are located in cis within an infecting genome. The same kinetics are also observed when the recombining elements are divided between VACV and transfected DNA. In contrast, recombination is delayed when the recombining sequences are located on different co-infecting viruses, and mature recombinants aren’t detected until well after late gene expression is well established. The delay supports the hypothesis that factories impede inter-viral recombination, but even after factories merge there remain further constraints limiting virus DNA mixing and recombinant gene assembly. This delay could be related to the continued presence of ER-derived membranes within the fused virosomes, membranes that may once have wrapped individual factories. PMID:27525721

  8. Creating Porcine Biomedical Models Through Recombineering

    Directory of Open Access Journals (Sweden)

    Lawrence B. Schook

    2006-03-01

    Full Text Available Recent advances in genomics provide genetic information from humans and other mammals (mouse, rat, dog and primates traditionally used as models as well as new candidates (pigs and cattle. In addition, linked enabling technologies, such as transgenesis and animal cloning, provide innovative ways to design and perform experiments to dissect complex biological systems. Exploitation of genomic information overcomes the traditional need to choose naturally occurring models. Thus, investigators can utilize emerging genomic knowledge and tools to create relevant animal models. This approach is referred to as reverse genetics. In contrast to ‘forward genetics’, in which gene(s responsible for a particular phenotype are identified by positional cloning (phenotype to genotype, the ‘reverse genetics’ approach determines the function of a gene and predicts the phenotype of a cell, tissue, or organism (genotype to phenotype. The convergence of classical and reverse genetics, along with genomics, provides a working definition of a ‘genetic model’ organism (3. The recent construction of phenotypic maps defining quantitative trait loci (QTL in various domesticated species provides insights into how allelic variations contribute to phenotypic diversity. Targeted chromosomal regions are characterized by the construction of bacterial artificial chromosome (BAC contigs to isolate and characterize genes contributing towards phenotypic variation. Recombineering provides a powerful methodology to harvest genetic information responsible for phenotype. Linking recombineering with gene-targeted homologous recombination, coupled with nuclear transfer (NT technology can provide ‘clones’ of genetically modified animals.

  9. Cutaneous allergy to human (recombinant DNA) insulin.

    Science.gov (United States)

    Grammer, L C; Metzger, B E; Patterson, R

    1984-03-16

    p6 report two cases of cutaneous allergy to human (recombinant DNA) insulin. Each patient had a history of systemic allergic reactions to porcine insulin and was at least as reactive to human as to porcine insulin by end-point cutaneous titration. Both patients' insulin allergy was managed with animal insulins and both have done well. Our experience with these two patients indicates that human insulin (rDNA) should not be expected to be efficacious in all patients with systemic allergy to insulin. PMID:6366262

  10. Hydrogen recombiner catalyst test supporting data

    Energy Technology Data Exchange (ETDEWEB)

    Britton, M.D.

    1995-01-19

    This is a data package supporting the Hydrogen Recombiner Catalyst Performance and Carbon Monoxide Sorption Capacity Test Report, WHC-SD-WM-TRP-211, Rev 0. This report contains 10 appendices which consist of the following: Mass spectrometer analysis reports: HRC samples 93-001 through 93-157; Gas spectrometry analysis reports: HRC samples 93-141 through 93-658; Mass spectrometer procedure PNL-MA-299 ALO-284; Alternate analytical method for ammonia and water vapor; Sample log sheets; Job Safety analysis; Certificate of mixture analysis for feed gases; Flow controller calibration check; Westinghouse Standards Laboratory report on Bois flow calibrator; and Sorption capacity test data, tables, and graphs.

  11. The landscape of recombination in African Americans

    OpenAIRE

    Anjali G Hinch; Tandon, Arti; Patterson, Nick; Song, Yunli; Rohland, Nadin; Palmer, Cameron D; Chen, Gary K.; Wang, Kai; Buxbaum, Sarah G.; Akylbekova, Meggie; Aldrich, Melinda C.; Ambrosone, Christine B.; Amos, Christopher; Bandera, Elisa V.; Berndt, Sonja I.

    2011-01-01

    Recombination, together with mutation, is the ultimate source of genetic variation in populations. We leverage the recent mixture of people of African and European ancestry in the Americas to build a genetic map measuring the probability of crossing-over at each position in the genome, based on about 2.1 million crossovers in 30,000 unrelated African Americans. At intervals of more than three megabases it is nearly identical to a map built in Europeans. At finer scales it differs significantl...

  12. Expression and purification of recombinant hemoglobin in Escherichia coli

    DEFF Research Database (Denmark)

    Natarajan, Chandrasekhar; Jiang, Xiaoben; Fago, Angela;

    2011-01-01

    the combined effects of induction temperature, induction time and E. coli expression strain on the solubility of recombinant deer mouse Hbs, we identified combinations of expression conditions that greatly enhanced the yield of recombinant protein and which also increased the efficiency of post......BACKGROUND: Recombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb) and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe...... a protocol for expressing Hbs with low intrinsic solubilities. Since the alpha- and beta-chain Hbs of different species span a broad range of solubilities, experimental protocols that have been optimized for expressing recombinant human HbA may often prove unsuitable for the recombinant expression...

  13. IV. Dissociative recombination of electrons and molecular ions

    International Nuclear Information System (INIS)

    The present state of the theory of the dissociative recombination of electrons and molecular ions is reviewed and its shortcomings shown. The mechanisms of direct and indirect dissociative processes are described. Several approximative methods employing the analogy with the recombination of atomic ions and electrons are used for the determination of the dissociative recombination factor. Analyzing the derived formulae the temperature dependence of the dissociative recombination factor is determined and the results are compared with experimental data obtained by several authors. The energy levels of atoms created at the dissociative recombination of He2+, Ar2+, and O2+ ions are described. Methods of measuring the recombination factor are listed. The existing experimental data are summarized and the possible explanation of the observed variations is presented. An exhaustive list of references is given. (J.U.)

  14. Recombinant allergens for allergen-specific immunotherapy: 10 years anniversary of immunotherapy with recombinant allergens.

    Science.gov (United States)

    Valenta, Rudolf; Linhart, B; Swoboda, I; Niederberger, V

    2011-06-01

    The broad applicability of allergen-specific immunotherapy for the treatment and eventually prevention of IgE-mediated allergy is limited by the poor quality and allergenic activity of natural allergen extracts that are used for the production of current allergy vaccines. Today, the genetic code of the most important allergens has been deciphered; recombinant allergens equalling their natural counterparts have been produced for diagnosis and immunotherapy, and a large panel of genetically modified allergens with reduced allergenic activity has been characterized to improve safety of immunotherapy and explore allergen-specific prevention strategies. Successful immunotherapy studies have been performed with recombinant allergens and hypoallergenic allergen derivatives and will lead to the registration of the first recombinant allergen-based vaccines in the near future. There is no doubt that recombinant allergen-based vaccination strategies will be generally applicable to most allergen sources, including respiratory, food and venom allergens and allow to produce safe allergy vaccines for the treatment of the most common forms of IgE-mediated allergies.

  15. Homologous recombination-mediated cloning and manipulation of genomic DNA regions using Gateway and recombineering systems

    Directory of Open Access Journals (Sweden)

    Kagale Sateesh

    2008-11-01

    Full Text Available Abstract Background Employing genomic DNA clones to characterise gene attributes has several advantages over the use of cDNA clones, including the presence of native transcription and translation regulatory sequences as well as a representation of the complete repertoire of potential splice variants encoded by the gene. However, working with genomic DNA clones has traditionally been tedious due to their large size relative to cDNA clones and the presence, absence or position of particular restriction enzyme sites that may complicate conventional in vitro cloning procedures. Results To enable efficient cloning and manipulation of genomic DNA fragments for the purposes of gene expression and reporter-gene studies we have combined aspects of the Gateway system and a bacteriophage-based homologous recombination (i.e. recombineering system. To apply the method for characterising plant genes we developed novel Gateway and plant transformation vectors that are of small size and incorporate selectable markers which enable efficient identification of recombinant clones. We demonstrate that the genomic coding region of a gene can be directly cloned into a Gateway Entry vector by recombineering enabling its subsequent transfer to Gateway Expression vectors. We also demonstrate how the coding and regulatory regions of a gene can be directly cloned into a plant transformation vector by recombineering. This construct was then rapidly converted into a novel Gateway Expression vector incorporating cognate 5' and 3' regulatory regions by using recombineering to replace the intervening coding region with the Gateway Destination cassette. Such expression vectors can be applied to characterise gene regulatory regions through development of reporter-gene fusions, using the Gateway Entry clones of GUS and GFP described here, or for ectopic expression of a coding region cloned into a Gateway Entry vector. We exemplify the utility of this approach with the Arabidopsis

  16. Characterization of recombination in the HLA class II region

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, M.; Carrington, M. [National Cancer Institute, Frederick, MD (United States); Noble, J. [Roche Molecular Systems, Almeda, CA (United States)] [and others

    1997-02-01

    Studies of linkage disequilibrium across the HLA class II region have been useful in predicting where recombination is most likely to occur. The strong associations between genes within the 85-kb region from DQB1 to DRB1 are consistent with low frequency of recombination in this segment of DNA. Conversely, a lack of association between alleles of TAP1 and TAP2 ({approximately}15 kb) has been observed, suggesting that recombination occurs here with relatively high frequency. Much of the HLA class II region has now been sequenced, providing the tools to undertake detailed analysis of recombination. Twenty-seven families containing one or two recombinant chromosomes within the 500-kb interval between the DPB1 and DRB1 genes were used to determine patterns of recombination across this region. SSCP analysis and microsatellite typing yielded identification of 127 novel polymorphic markers distributed throughout the class II region, allowing refinement of the site of crossover in 30 class II recombinant chromosomes. The three regions where recombination was observed most frequently are as follows: the 45-kb interval between HLA-DNA and RING3 (11 cases), the 50-kb interval between DQB3 and DQB1 (6 cases), and an 8.8-kb segment of the TAP2 gene (3 cases). Six of the 10 remaining recombinants await further characterization, pending identification of additional informative markers, while four recombinants were localized to other intervals (outliers). Analysis of association between markers flanking HLA-DNA to RING3 (45 kb), as well as TAP1 to TAP2 (15 kb), by use of independent CEPH haplotypes indicated little or no linkage disequilibrium, supporting the familial recombination data. A notable sequence motif located within a region associated with increased rates of recombination consisted of a (TGGA){sub 12} tandem repeat within the TAP2 gene. 74 refs., 3 figs., 2 tabs.

  17. Development of Recombinant Cationic Polymers for Gene Therapy Research

    OpenAIRE

    Canine, Brenda F.; Hatefi, Arash

    2010-01-01

    Cationic polymers created through recombinant DNA technology have the potential to fill a void in the area of gene delivery. The recombinant cationic polymers to be discussed here are amino acid based polymers synthesized in E.coli with the purpose to not only address the major barriers to efficient gene delivery but offer safety, biodegradability, targetability and cost-effectiveness. This review helps the readers to get a better understanding about the evolution of recombinant cationic poly...

  18. Direct demonstration of retroviral recombination in a rhesus monkey.

    OpenAIRE

    Wooley, D P; Smith, R A; Czajak, S; Desrosiers, R C

    1997-01-01

    Recombination may be an important mechanism for increasing variation in retroviral populations. Retroviral recombination has been demonstrated in tissue culture systems by artificially creating doubly infected cells. Evidence for retroviral recombination in vivo is indirect and is based principally on the identification of apparently mosaic human immunodeficiency virus type 1 genomes from phylogenetic analyses of viral sequences. We infected a rhesus monkey with two different molecularly clon...

  19. The landscape of recombination in African Americans.

    Science.gov (United States)

    Hinch, Anjali G; Tandon, Arti; Patterson, Nick; Song, Yunli; Rohland, Nadin; Palmer, Cameron D; Chen, Gary K; Wang, Kai; Buxbaum, Sarah G; Akylbekova, Ermeg L; Aldrich, Melinda C; Ambrosone, Christine B; Amos, Christopher; Bandera, Elisa V; Berndt, Sonja I; Bernstein, Leslie; Blot, William J; Bock, Cathryn H; Boerwinkle, Eric; Cai, Qiuyin; Caporaso, Neil; Casey, Graham; Cupples, L Adrienne; Deming, Sandra L; Diver, W Ryan; Divers, Jasmin; Fornage, Myriam; Gillanders, Elizabeth M; Glessner, Joseph; Harris, Curtis C; Hu, Jennifer J; Ingles, Sue A; Isaacs, William; John, Esther M; Kao, W H Linda; Keating, Brendan; Kittles, Rick A; Kolonel, Laurence N; Larkin, Emma; Le Marchand, Loic; McNeill, Lorna H; Millikan, Robert C; Murphy, Adam; Musani, Solomon; Neslund-Dudas, Christine; Nyante, Sarah; Papanicolaou, George J; Press, Michael F; Psaty, Bruce M; Reiner, Alex P; Rich, Stephen S; Rodriguez-Gil, Jorge L; Rotter, Jerome I; Rybicki, Benjamin A; Schwartz, Ann G; Signorello, Lisa B; Spitz, Margaret; Strom, Sara S; Thun, Michael J; Tucker, Margaret A; Wang, Zhaoming; Wiencke, John K; Witte, John S; Wrensch, Margaret; Wu, Xifeng; Yamamura, Yuko; Zanetti, Krista A; Zheng, Wei; Ziegler, Regina G; Zhu, Xiaofeng; Redline, Susan; Hirschhorn, Joel N; Henderson, Brian E; Taylor, Herman A; Price, Alkes L; Hakonarson, Hakon; Chanock, Stephen J; Haiman, Christopher A; Wilson, James G; Reich, David; Myers, Simon R

    2011-07-20

    Recombination, together with mutation, gives rise to genetic variation in populations. Here we leverage the recent mixture of people of African and European ancestry in the Americas to build a genetic map measuring the probability of crossing over at each position in the genome, based on about 2.1 million crossovers in 30,000 unrelated African Americans. At intervals of more than three megabases it is nearly identical to a map built in Europeans. At finer scales it differs significantly, and we identify about 2,500 recombination hotspots that are active in people of West African ancestry but nearly inactive in Europeans. The probability of a crossover at these hotspots is almost fully controlled by the alleles an individual carries at PRDM9 (P value < 10(-245)). We identify a 17-base-pair DNA sequence motif that is enriched in these hotspots, and is an excellent match to the predicted binding target of PRDM9 alleles common in West Africans and rare in Europeans. Sites of this motif are predicted to be risk loci for disease-causing genomic rearrangements in individuals carrying these alleles. More generally, this map provides a resource for research in human genetic variation and evolution.

  20. Dissociative recombination of N2H+

    Science.gov (United States)

    dos Santos, S. Fonseca; Ngassam, V.; Orel, A. E.; Larson, Å.

    2016-08-01

    The direct and indirect mechanisms of dissociative recombination of N2H+ are theoretically studied. At low energies, the electron capture is found to be driven by recombination into bound Rydberg states, while at collision energies above 0.1 eV, the direct capture and dissociation along electronic resonant states becomes important. Electron-scattering calculations using the complex Kohn variational method are performed to obtain the scattering matrix as well as energy positions and autoionization widths of resonant states. Potential-energy surfaces of electronic bound states of N2H and N2H+ are computed using structure calculations with the multireference configuration interaction method. The cross section for the indirect mechanism is calculated using a vibrational frame transformation of the elements of the scattering matrix at energies just above the ionization threshold. Here vibrational excitations of the ionic core from v =0 to v =1 and v =2 for all three normal modes are considered and autoionization is neglected. The cross section for the direct dissociation along electronic resonant states is computed with wave-packet calculations using the multiconfiguration time-dependent Hartree method, where all three internal degrees of freedom are considered. The calculated cross sections are compared to measurements.

  1. Recombinant antigens for immunodiagnosis of cystic echinococcosis

    Directory of Open Access Journals (Sweden)

    Li Jun

    2004-01-01

    Full Text Available Three cDNAs, termed EpC1, TPxEg and EgG5, were isolated by immunoscreening from an Echinococcus granulosus cDNA library. The recombinant phages exhibited strong reactivity with sera from humans with confirmed cystic echinococcosis (CE and with sera from mice infected with E. granulosus oncospheres. The cDNAs were subcloned into a pET vector, expressed as fusion proteins tagged with GST and affinity purified against the GST tag. Of the three recombinant proteins, EpC1 achieved the highest performance for serodiagnosis of CE in Western blot analysis using a panel of clinically defined human sera to initially address the sensitivity and specificity of the molecules. The protein yielded an overall sensitivity of 92.2% and specificity of 95.6%, levels unprecedented taking into account the large panel of 896 human sera that were tested. The strategy used may also prove suitable for improved immunodiagnosis of other parasitic infections.

  2. Immunoglobulin class-switch recombination deficiencies.

    Science.gov (United States)

    Durandy, Anne; Kracker, Sven

    2012-01-01

    Immunoglobulin class-switch recombination deficiencies (Ig-CSR-Ds) are rare primary immunodeficiencies characterized by defective switched isotype (IgG/IgA/IgE) production. Depending on the molecular defect in question, the Ig-CSR-D may be combined with an impairment in somatic hypermutation (SHM). Some of the mechanisms underlying Ig-CSR and SHM have been described by studying natural mutants in humans. This approach has revealed that T cell-B cell interaction (resulting in CD40-mediated signaling), intrinsic B-cell mechanisms (activation-induced cytidine deaminase-induced DNA damage), and complex DNA repair machineries (including uracil-N-glycosylase and mismatch repair pathways) are all involved in class-switch recombination and SHM. However, several of the mechanisms required for full antibody maturation have yet to be defined. Elucidation of the molecular defects underlying the diverse set of Ig-CSR-Ds is essential for understanding Ig diversification and has prompted better definition of the clinical spectrum of diseases and the development of increasingly accurate diagnostic and therapeutic approaches. PMID:22894609

  3. [Telomere Recombination in Normal Mammalian Cells].

    Science.gov (United States)

    Zhdanova, N S; Rubtsov, N B

    2016-01-01

    Two mechanisms of telomere length maintenance are known to date. The first includes the use of a special enzymatic telomerase complex to solve the problems that arise during the replication of linear DNA in a normal diploid and part of tumor cells. Alternative lengthening of telomeres (ALT), which is based on the homologous recombination of telomere DNA, represents the second mechanism. Until recently, ALT was assumed to be expressed only in 15-20% of tumors lacking active telomerase and, together with telomerase reactivation represented one of two possibilities to overcome the replicative senescence observed in somatic mammalian cells due to aging or during cell culturing in vitro. Previously described sporadic cases of combinations of the two mechanisms of telomere length maintenance in several cell lines in vitro were attributed to the experimental design rather than to a real biological phenomenon, since active cellular division without active telomerase was considered to be the "gold standard" of ALT. The present review describes the morphological and functional reorganizations of mammalian telomeres observed with ALT activation, as well as recently observed,and well-documented cases of combinations between ALT-like and telomerase-dependent mechanisms in mammalian cells. The possible role of telomere recombination in telomerase-dependent cells is discussed. PMID:27183789

  4. Sorbitol production using recombinant Zymomonas mobilis strain.

    Science.gov (United States)

    Liu, Changjun; Dong, Hongwei; Zhong, Jianjiang; Ryu, Dewey D Y; Bao, Jie

    2010-07-20

    A recombinant Zymomonas mobilis strain harboring the plasmid pHW20a-gfo for over-expression of glucose-fructose oxidoreductase (GFOR) was constructed. The specific activity of GFOR enzyme in the new recombinant strain was at least two folds greater than that in the wild strain. The maximum GFOR activity achieved in terms of the volumetric, and the cellular were 2.59 U ml(-1), and 0.70 U mg(-1), respectively, in the batch cultures. A significant improvement of the bioconversion process for the production of sorbitol and gluconic acid from glucose and fructose was made using divalent metal ions which drastically reduced the ethanol yield and significantly increased the yield of target product. Among several divalent metal ions evaluated, Zn(2+) was found to be most effective by inhibiting the Entner-Doudoroff pathway enzymes. The yield of the byproduct ethanol was reduced from 16.7 to 1.8 gl(-1) and the sorbitol yield was increased to almost 100% from 89%. The Ca(2+) enhanced the sorbitol yield and the formation of calcium gluconate salt made the separation of gluconate from the reaction system easier.

  5. H2 recombination on interstellar grains

    International Nuclear Information System (INIS)

    From a consideration of relevant theoretical and experimental data it is concluded that H atoms (but not H2 molecules) will be chemisorbed on interstellar graphite grains, with H2 formation proceeding efficiently for graphite grain temperatures less than 70 K. It is argued that graphite grains will act as the principle sites for H2 formation, with a formation rate of Rapprox. =4 x 10/sup -17/ cm3 s/sup -1/. Heating by H2 molecules formed by surface recombination is analyzed in the context of the available experimental data, and a heating rate is derived and compared with other suggested cloud heating mechanisms. We conclude that H2 recombination will provide the largest heat source in diffuse clouds if the albedo of interstellar dust in the 912--1200 A region is high (approx.0.9), whereas if the albedo in this wavelength region is lower (approx.0.5), photoelectron ejection from grains will tend to predominate, and can explain observed cloud temperatures with a carbon depletion factor of approximately 2, a factor attributable to a normal interstellar abundance of graphite grains

  6. [Enzymatic control of homologous recombination in Escherichia coli cells and hyper-recombination].

    Science.gov (United States)

    Bakhlanova, I V; Dudkina, A V; Baĭtin, D M

    2013-01-01

    The RecA protein is a major enzyme of homologous recombination in bacterial cell. Forming a right-handed helical filament on ssDNA, it provides a homology search between two DNA molecules and homologous strand exchange. The RecA protein not only defends the cell from exposure to ionizing radiation and UV-irradiation, but also ensures the recombination process in the course of normal cell growth. A number of wild-type or mutant RecA proteins demonstrate increased recombinogenic properties in vitro and in vivo as compared with the wild-type RecA protein from Escherichia coli, which leads to hyper-recombination. The hyper-rec activity of RecA proteins during the recombination process in many depends on the filamentation dynamics on ssDNA and DNA-transferase properties. Changes in filamentation and DNA-transferase abilities of RecA protein may be the result of not only specific amino-acid substitutions, but also the functioning of the cell enzymatic apparatus, including such proteins as RecO, RecR, RecF, RecX, DinI, SSB, PsiB. To date, the function of each of these proteins is identified at the molecular level. However, the role of some of them in the cell metabolism remains to be seen. Increase in recombination in vivo is not always useful for a cell and faces various limitations. Moreover, in the bacterial cell some mechanisms are activated, that cause genomic reorganization, directed to suppress the expression of hyper-active RecA protein. The ways of hyper-active RecA protein regulation are very interesting, and they are studied in different model systems. PMID:23808153

  7. Sex, not genotype, determines recombination levels in mice.

    Science.gov (United States)

    Lynn, Audrey; Schrump, Stefanie; Cherry, Jonathan; Hassold, Terry; Hunt, Patricia

    2005-10-01

    Recombination, the precise physical breakage and rejoining of DNA between homologous chromosomes, plays a central role in mediating the orderly segregation of meiotic chromosomes in most eukaryotes. Despite its importance, the factors that control the number and placement of recombination events within a cell remain poorly defined. The rate of recombination exhibits remarkable species specificity, and, within a species, recombination is affected by the physical size of the chromosome, chromosomal location, proximity to other recombination events (i.e., chiasma interference), and, intriguingly, the sex of the transmitting parent. To distinguish between simple genetic and nongenetic explanations of sex-specific recombination differences in mammals, we compared recombination in meiocytes from XY sex-reversed and XO females with that in meiocytes from XX female and XY male mice. The rate and pattern of recombination in XY and XO oocytes were virtually identical to those in normal XX females, indicating that sex, not genotype, is the primary determinant of meiotic recombination patterns in mammals.

  8. Rogue athletes and recombinant DNA technology: challenges for doping control.

    Science.gov (United States)

    Azzazy, Hassan M E; Mansour, Mai M H

    2007-10-01

    The quest for athletic excellence holds no limit for some athletes, and the advances in recombinant DNA technology have handed these athletes the ultimate doping weapons: recombinant proteins and gene doping. Some detection methods are now available for several recombinant proteins that are commercially available as pharmaceuticals and being abused by dopers. However, researchers are struggling to come up with efficient detection methods in preparation for the imminent threat of gene doping, expected in the 2008 Olympics. This Forum article presents the main detection strategies for recombinant proteins and the forthcoming detection strategies for gene doping as well as the prime analytical challenges facing them.

  9. Homologous recombination: from model organisms to human disease

    NARCIS (Netherlands)

    M. Modesti (Mauro); R. Kanaar (Roland)

    2001-01-01

    textabstractRecent experiments show that properly controlled recombination between homologous DNA molecules is essential for the maintenance of genome stability and for the prevention of tumorigenesis.

  10. Photoionization and electron-ion recombination of Ti I

    Science.gov (United States)

    Nahar, Sultana N.

    2016-07-01

    Study of the inverse processes of photoionization and electron-ion recombination of (Ti I + h ν ⇋ Ti II + e) using the unified method is reported. The method, based on close coupling (CC) approximation and R-matrix method, subsumes both the radiative recombination (RR) and dielectronic recombination (DR) in a unified manner and provides state-specific and total electron-ion recombination rate coefficients which are self-consistent with the state-specific photoionization cross sections. The present results include state-specific electron-ion recombination rates (αRC(i))and partial photoionization cross sections (σPI(i)) leaving the ion in the ground state of 813 bound states with n ≤ 10 and l ≤ 9 of Ti I. Various features of state-specific and total electron-ion recombination with temperature, and the corresponding photoionization cross sections with energies are discussed with illustrations. Due to closely lying excited states near the ground state of the core, photoionization cross sections show presence of narrow Rydberg resonances in low energy region near the ionization threshold. Many excited states also show broad and enhanced Seaton resonances due to PEC (photo-excitation-of-core) which contribute to the high temperature recombination. The total recombination rate coefficient is found to show a low hump around temperature 280 K and a high dielectronic recombination peak at temperature 25,000 K. Total spectrum of recombination cross sections and rates with photoelectron energy are also presented for experimental observation. Calculations were carried out using a CC wave function expansion of 36 states of the core ion Ti II. The large set of data for recombination rates and partial photoionization cross sections with resonances should provide a complete and accurate modelings of plasmas.

  11. Some aspects on four quarks recombination

    CERN Document Server

    Sanchez, G Toledo

    2016-01-01

    We have performed a 3-D Monte Carlo simulation of a system composed of two identical light quarks ($qq$) and two identical antiquarks ($\\bar Q\\bar Q$) and determined whether it is energetically more favorable to form a tetraquark or two mesons, as a function of the interparticle separation distance which, for a fixed number of particles, can be identified as a particle density. In this proceedings, we highlight the main results and elaborate on the implications in properties like the correlation function for two-mesons and characterize the isolated diquark correlation function. We analize the four-body potential evolution and exhibit its linear behavior as a function of the invariant distance. We track the dynamical flipping among configurations to determine the recombination probability, exhibiting the importance of the tetraquark state.

  12. Acid phosphatase production by recombinant Arxula adeninivorans.

    Science.gov (United States)

    Minocha, Neha; Kaur, Parvinder; Satyanarayana, T; Kunze, G

    2007-08-01

    Acid phosphatase production by recombinant Arxula adeninivorans was carried out in submerged fermentation. Using the Plackett-Burman design, three fermentation variables (pH, sucrose concentration, and peptone concentration) were identified to significantly affect acid phosphatase and biomass production, and these were optimized using response surface methodology of central composite design. The highest enzyme yields were attained in the medium with 3.9% sucrose and 1.6% peptone at pH 3.8. Because of optimization, 3.86- and 4.19-fold enhancement in enzyme production was achieved in shake flasks (17,054 U g(-1) DYB) and laboratory fermenter (18,465 U g(-1) DYB), respectively. PMID:17541580

  13. Initiation of Meiotic Recombination in Mammals

    Directory of Open Access Journals (Sweden)

    Rajeev Kumar

    2010-12-01

    Full Text Available Meiotic recombination is initiated by the induction of programmed DNA double strand breaks (DSBs. DSB repair promotes homologous interactions and pairing and leads to the formation of crossovers (COs, which are required for the proper reductional segregation at the first meiotic division. In mammals, several hundred DSBs are generated at the beginning of meiotic prophase by the catalytic activity of SPO11. Currently it is not well understood how the frequency and timing of DSB formation and their localization are regulated. Several approaches in humans and mice have provided an extensive description of the localization of initiation events based on CO mapping, leading to the identification and characterization of preferred sites (hotspots of initiation. This review presents the current knowledge about the proteins known to be involved in this process, the sites where initiation takes place, and the factors that control hotspot localization.

  14. Recombinant Brucella abortus gene expressing immunogenic protein

    Energy Technology Data Exchange (ETDEWEB)

    Mayfield, J.E.; Tabatabai, L.B.

    1991-06-11

    This patent describes a synthetic recombinant DNA molecule containing a DNA sequence. It comprises a gene of Brucella abortus encoding an immunogenic protein having a molecular weight of approximately 31,000 daltons as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis under denaturing conditions, the protein having an isoelectric point around 4.9, and containing a twenty-five amino acid sequence from its amino terminal end consisting of Gln-Ala-Pro-Thr-Phe-Phe-Arg-Ile-Gly-Thr-Gly-Gly-Thr-Ala-Gly-Thr-Tyr-Tyr-Pro-Ile-Gly-Gly-Leu-Ile-Ala, wherein Gln, Ala, Pro, Thr, Phe, Arg, Ile, Gly, Tyr, and Leu, respectively, represent glutamine, alanine, proline, threonine, phenylalanine, arginine, isolecuine, glycine, tyrosine, and leucine.

  15. Radio recombination lines from H II regions

    International Nuclear Information System (INIS)

    Radio recombination lines have been observed from forty-six H II regions. The Arecibo 1000-foot radio telescope was used to provide high sensitivity and high angular resolution at 1400 MHz (gain approx. 7.70K/Jy, HPBW = 3:2) and 2372 MHZ (gain approx. 6.30K/Jy, HPBW = 2'). Observations were made at 1400 MHz in the frequency switching mode, and at 2372 MHz in the total power mode. Gaussians were fit to be observed lines to derive velocities, line widths, and line temperatures. From the velocities kinematic distances were derived. For eleven sources H I absorption measurements were also made. The absorption spectra enabled the kinematic distance ambiguity to be resolved for some sources. The absorption spectra themselves were found to have extremely sharp, non-gaussian edges. One explanation for these is a model where the interstellar medium contains many H I cloudlets with T/sub s/less than or equal to 1000K and turbulent velocities less than or equal to 3 km/s. The H I absorption spectrum is then a superposition of many narrow gaussian profiles. It was also found from a comparison of H I absorption velocities with radio recombination line velocities that peculiar motions exist in the interstellar medium with velocities of up to 10 km/s. Using the measured line temperatures and continuum temperatures, estimates were desired of emission measures, electron temperatures, and electron densities, using a non-LTE analysis. Non-LTE effects were important only for the hottest and densest H II regions. The non-LTE calculations were checked through a comparison derivation of electron temperatures using hydrogen beta lines

  16. Functional, Responsive Materials Assembled from Recombinant Oleosin

    Science.gov (United States)

    Hammer, Daniel

    Biological cells are surrounded by a plasma membrane made primarily of phospholipids that form a bilayer. This membrane is permselective and compartmentalizes the cell. A simple form of artificial cell is the vesicle, in which a phospholipid bilayer membrane surrounds an aqueous solution. However, there is no a priori reason why a membrane needs to be made of phospholipids. It could be made of any surfactant that forms a bilayer. We have assembled membranes and other structures from the recombinant plant protein oleosin. The ability to assemble from a recombinant protein means that every molecule is identical, we have complete control over the sequence, and hence can build in designer functionality with high fidelity, including adhesion and enzymatic activity. Such incorporation is trivial using the tools of molecular biology. We find that while many variants of oleosin make membranes, others make micelles and sheets. We show how the type of supramolecular structure can be altered by the conditions of solvent, such as ionic strength, and the architecture of the surfactant itself. We show that protease cleavable domains can be incorporated within oleosin, and be engineered to protect other functional domains such as adhesive motifs, to make responsive materials whose activity and shape depend on the action of proteases. We will also present the idea of making ``Franken''-oleosins, where large domains of native oleosin are replaced with domains from other functional proteins, to make hybrids conferred by the donor protein. Thus, we can view oleosin as a template upon which a vast array of designer functionalities can be imparted..

  17. Phenylbutyrate inhibits homologous recombination induced by camptothecin and methyl methanesulfonate

    DEFF Research Database (Denmark)

    Kaiser, Gitte Schalck; Germann, Susanne Manuela; Westergaard, Tine;

    2011-01-01

    Homologous recombination is accompanied by extensive changes to chromatin organization at the site of DNA damage. Some of these changes are mediated through acetylation/deacetylation of histones. Here, we show that recombinational repair of DNA damage induced by the anti-cancer drug camptothecin...

  18. Dissociative recombination of HeH[sup +]: A reexamination

    Energy Technology Data Exchange (ETDEWEB)

    Yousif, F.B.; Mitchell, J.B.A.; Rogelstad, M.; Le Paddelec, A.; Canosa, A.; Chibisov, M.I. (Department of Physics and Center for Chemical Physics, University of Western Ontario, London, Ontario, N6A3K7 (Canada))

    1994-06-01

    A high-energy-resolution study of the dissociative recombination of HeH[sup +] has been performed. A theoretical analysis has indicated that the recombination at low energy is due to the presence of a metastable triplet-state component of the ion beam.

  19. Tailoring Charge Recombination in Photoelectrodes Using Oxide Nanostructures

    DEFF Research Database (Denmark)

    Iandolo, Beniamino; Wickman, Björn; Svensson, Elin;

    2016-01-01

    Optimizing semiconductor devices for solar energy conversion requires an explicit control of the recombination of photogenerated electron−hole pairs. Here we show how the recombination of charge carriers can be controlled in semiconductor thin films by surface patterning with oxide nanodisks. The...

  20. Mitochondrial recombination increases with age in Podospora anserina

    NARCIS (Netherlands)

    van Diepeningen, Anne D; Goedbloed, Daniël J; Slakhorst, S Marijke; Koopmanschap, A Bertha; Maas, Marc F P M; Hoekstra, Rolf F; Debets, Alfons J M

    2010-01-01

    With uniparental inheritance of mitochondria, there seems little reason for homologous recombination in mitochondria, but the machinery for mitochondrial recombination is quite well-conserved in many eukaryote species. In fungi and yeasts heteroplasmons may be formed when strains fuse and transfer o

  1. The current state of recombinant allergens for immunotherapy

    DEFF Research Database (Denmark)

    Pauli, Gabrielle; Malling, H-J

    2010-01-01

    the patient may not be sensitized. Recombinant allergens offer a possibility to use well defined molecules with consistent pharmaceutical quality defined in mass units. The proof of concept of the clinical efficacy of recombinant allergens is based on two studies published as full articles....

  2. A Heritable Recombination system for synthetic Darwinian evolution in yeast.

    Science.gov (United States)

    Romanini, Dante W; Peralta-Yahya, Pamela; Mondol, Vanessa; Cornish, Virginia W

    2012-12-21

    Genetic recombination is central to the generation of molecular diversity and enhancement of evolutionary fitness in living systems. Methods such as DNA shuffling that recapitulate this diversity mechanism in vitro are powerful tools for engineering biomolecules with useful new functions by directed evolution. Synthetic biology now brings demand for analogous technologies that enable the controlled recombination of beneficial mutations in living cells. Thus, here we create a Heritable Recombination system centered around a library cassette plasmid that enables inducible mutagenesis via homologous recombination and subsequent combination of beneficial mutations through sexual reproduction in Saccharomyces cerevisiae. Using repair of nonsense codons in auxotrophic markers as a model, Heritable Recombination was optimized to give mutagenesis efficiencies of up to 6% and to allow successive repair of different markers through two cycles of sexual reproduction and recombination. Finally, Heritable Recombination was employed to change the substrate specificity of a biosynthetic enzyme, with beneficial mutations in three different active site loops crossed over three continuous rounds of mutation and selection to cover a total sequence diversity of 10(13). Heritable Recombination, while at an early stage of development, breaks the transformation barrier to library size and can be immediately applied to combinatorial crossing of beneficial mutations for cell engineering, adding important features to the growing arsenal of next generation molecular biology tools for synthetic biology. PMID:23412545

  3. Construction and Characterization of a Recombinant Invertebrate Iridovirus

    NARCIS (Netherlands)

    Ozgen, A.; Muratoglu, H.; Demirbag, Z.; Vlak, J.M.; Oers, van M.M.; Nalcacioglu, R.

    2014-01-01

    Chilo iridescent virus (CIV), officially named Insect iridescent virus 6 (IIV6), is the type species of the genus Iridovirus (family Iridoviridae). In this paper we constructed a recombinant CIV, encoding the green fluorescent protein (GFP). This recombinant can be used to investigate viral replicat

  4. Electron recombination with tungsten ions with open f-shells

    CERN Document Server

    Harabati, C; Flambaum, V V; Dzuba, V A

    2016-01-01

    We calculate the electron recombination rates with target ions W$^{q+}$, $q = 18$ -- $25$, as functions of electron energy and electron temperature (i.e. the rates integrated over the Maxwellian velocity distribution). Comparison with available experimental data for W$^{18+}$, W$^{19+}$, and W$^{20+}$ is used as a test of our calculations. Our predictions for W$^{21+}$, W$^{22+}$, W$^{23+}$, W$^{24+}$, and W$^{25+}$ (where the experimental data are not available) may be used for plasma modelling in thermonuclear reactors. All of these ions have an open electron $f$-shell and have an extremely dense spectrum of chaotic many-electron compound resonances which enhance the recombination rates by 2-3 orders of magnitude in comparison with the direct electron recombination. Conventional dielectronic recombination theory is not directly applicable in this case. Instead, we developed a statistical theory based on the properties of chaotic eigenstates. This theory describes a multi-electronic recombination (extension ...

  5. Recombinant human bone morphogenetic protein induces bone formation

    International Nuclear Information System (INIS)

    The authors have purified and characterized active recombinant human bone morphogenetic protein (BMP) 2A. Implantation of the recombinant protein in rats showed that a single BMP can induce bone formation in vivo. A dose-response and time-course study using the rat ectopic bone formation assay revealed that implantation of 0.5-115 μg of partially purified recombinant human BMP-2A resulted in cartilage by day 7 and bone formation by day 14. The time at which bone formation occurred was dependent on the amount of BMP-2A implanted; at high doses bone formation could be observed at 5 days. The cartilage- and bone-inductive activity of the recombinant BMP-2A is histologically indistinguishable from that of bone extracts. Thus, recombinant BMP-2A has therapeutic potential to promote de novo bone formation in humans

  6. Colony mutants of compatible nocardiae displaying variations in recombining capacity.

    Science.gov (United States)

    Brownell, G H; Walsh, R S

    1972-03-01

    Colonial morphology mutants of Nocardia erythropolis were isolated following ultraviolet (UV) irradiation. The alleles rou-1/smo-1 were located by recombinant analysis and found to be linked to previously mapped characters. On the basis of recombinant class type patterns obtained from various selective characters it was postulated that the rou-1 allele may span a region of unique nucleotides in the Mat-Ce genome. Recombination frequencies of rou-1 and smo-2 bearing mutants of the Mat-Ce mating type were found to differ by over 1000 fold. Attempts to demonstrate that low recombination frequencies produced by the Smo mutants were due to Rec(-) genes were unsuccessful. No increased sensitivity to either UV or X irradiation was observed by the Smo mutants. Acriflavine treatment of either Rou or Smo colony mutants failed to accelerate reversion or to alter the recombining potentials of the mutants.

  7. Sex recombination, and reproductive fitness: an experimental study using Paramecium

    Energy Technology Data Exchange (ETDEWEB)

    Nyberg, D.

    1982-08-01

    The effect of sex and recombination on reproductive fitness are measured using five wild stocks of Paramecium primaurelia. Among the wild stocks there were highly significant differences in growth rates. No hybrid had as low a fitness as the least fit parental stock. Recombination produced genotypes of higher fitness than those of either parent only in the cross between the two stocks of lowest fitness. The increase in variance of fitness as a result of recombination was almost exclusively attributable to the generation lines with low fitness. The fitness consequences of sexuality and mate choice were stock specific; some individuals leaving the most descendants by inbreeding, others by outcrossing. For most crosses the short-term advantage of sex, if any, accrue from the fusion of different gametes (hybrid vigor) and not from recombination. Since the homozygous genotype with the highest fitnes left the most progeny by inbreeding (no recombination), the persistence of conjugation in P. primaurelia is paradoxical. (JMT)

  8. Patterns of Human Immunodeficiency Virus type 1 recombination ex vivo provide evidence for coadaptation of distant sites, resulting in purifying selection for intersubtype recombinants during replication

    DEFF Research Database (Denmark)

    Galli, Andrea; Kearney, Mary; Nikolaitchik, Olga A;

    2010-01-01

    in human populations. We hypothesize that sequence diversity affects the emergence of viable recombinants by decreasing recombination events and reducing the ability of the recombinants to replicate. To test our hypothesis, we compared recombination between two viruses containing subtype B pol genes (B...

  9. Expression and purification of recombinant hemoglobin in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Chandrasekhar Natarajan

    Full Text Available BACKGROUND: Recombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe a protocol for expressing Hbs with low intrinsic solubilities. Since the α- and β-chain Hbs of different species span a broad range of solubilities, experimental protocols that have been optimized for expressing recombinant human HbA may often prove unsuitable for the recombinant expression of wildtype and mutant Hbs of other species. METHODOLOGY/PRINCIPAL FINDINGS: As a test case for our expression system, we produced recombinant Hbs of the deer mouse (Peromyscus maniculatus, a species that has been the subject of research on mechanisms of Hb adaptation to hypoxia. By experimentally assessing the combined effects of induction temperature, induction time and E. coli expression strain on the solubility of recombinant deer mouse Hbs, we identified combinations of expression conditions that greatly enhanced the yield of recombinant protein and which also increased the efficiency of post-translational modifications. CONCLUSION/SIGNIFICANCE: Our protocol should prove useful for the experimental study of recombinant Hbs in many non-human animals. One of the chief advantages of our protocol is that we can express soluble recombinant Hb without co-expressing molecular chaperones, and without the need for additional reconstitution or heme-incorporation steps. Moreover, our plasmid construct contains a combination of unique restriction sites that allows us to produce recombinant Hbs with different α- and β-chain subunit combinations by means of cassette mutagenesis.

  10. Multiple barriers to recombination between divergent HIV-1 variants revealed by a dual-marker recombination assay

    DEFF Research Database (Denmark)

    Nikolaitchik, Olga A; Galli, Andrea; Moore, Michael D;

    2011-01-01

    Recombination is a major force for generating human immunodeficiency virus type 1 (HIV-1) diversity and produces numerous recombinants circulating in the human population. We previously established a cell-based system using green fluorescent protein gene (gfp) as a reporter to study the mechanisms...

  11. Effects of the rad52 gene on recombination in Saccharomyces cerevisiae. [Comparison of. gamma. -, uv-induced meiotic and spontaneous mitotic recombination

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, S.; Prakash, L.; Burke, W.; Montelone, B.A.

    1979-01-01

    Effects of the rad52 mutation in Saccharomyces cerevisiae on meiotic, ..gamma..-ray-induced, uv-induced, and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Intra- and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the hisl-1/hisl-315 and trp5-2/trp5-48 heteroalleles. Gene-centromere recombination was also not observed in rad52/rad52 diploids. No ..gamma..-ray-induced intragenic mitotic recombination is seen in rad52/rad52 diploids and uv-induced intragenic recombination is greatly reduced. However, spontaneous mitotic recombination is not similarly affected. The RAD52 gene thus functions in recombination in meiosis and in ..gamma..-ray and uv-induced mitotic recombination but not in spontaneous mitotic recombination.

  12. 75 FR 42114 - Office of Biotechnology Activities; Recombinant DNA Research: Proposed Action Under the NIH...

    Science.gov (United States)

    2010-07-20

    ... HUMAN SERVICES National Institutes of Health Office of Biotechnology Activities; Recombinant DNA Research: Proposed Action Under the NIH Guidelines for Research Involving Recombinant DNA Molecules (NIH... transgenic rodents by recombinant DNA technology must be registered with the Institutional...

  13. Evidence of recombination within human alpha-papillomavirus

    Directory of Open Access Journals (Sweden)

    Carvajal-Rodríguez Antonio

    2007-03-01

    Full Text Available Abstract Background Human papillomavirus (HPV has a causal role in cervical cancer with almost half a million new cases occurring each year. Presence of the carcinogenic HPV is necessary for the development of the invasive carcinoma of the genital tract. Therefore, persistent infection with carcinogenic HPV causes virtually all cervical cancers. Some aspects of the molecular evolution of this virus, as the putative importance of recombination in its evolutionary history, are an opened current question. In addition, recombination could also be a significant issue nowadays since the frequency of co-infection with more than one HPV type is not a rare event and, thus, new recombinant types could be currently being generated. Results We have used human alpha-PV sequences from the public database at Los Alamos National Laboratory to report evidence that recombination may exist in this virus. A model-based population genetic approach was used to infer the recombination signal from the HPV DNA sequences grouped attending to phylogenetic and epidemiological information, as well as to clinical manifestations. Our results agree with recently published ones that use a different methodology to detect recombination associated to the gene L2. In addition, we have detected significant recombination signal in the genes E6, E7, L2 and L1 at different groups, and importantly within the high-risk type HPV16. The method used has recently been shown to be one of the most powerful and reliable procedures to detect the recombination signal. Conclusion We provide new support to the recent evidence of recombination in HPV. Additionally, we performed the recombination estimation assuming the best-fit model of nucleotide substitution and rate variation among sites, of the HPV DNA sequence sets. We found that the gene with recombination in most of the groups is L2 but the highest values were detected in L1 and E6. Gene E7 was recombinant only within the HPV16 type. The

  14. Phylogenetic and recombination analysis of tomato spotted wilt virus.

    Directory of Open Access Journals (Sweden)

    Sen Lian

    Full Text Available Tomato spotted wilt virus (TSWV severely damages and reduces the yield of many economically important plants worldwide. In this study, we determined the whole-genome sequences of 10 TSWV isolates recently identified from various regions and hosts in Korea. Phylogenetic analysis of these 10 isolates as well as the three previously sequenced isolates indicated that the 13 Korean TSWV isolates could be divided into two groups reflecting either two different origins or divergences of Korean TSWV isolates. In addition, the complete nucleotide sequences for the 13 Korean TSWV isolates along with previously sequenced TSWV RNA segments from Korea and other countries were subjected to phylogenetic and recombination analysis. The phylogenetic analysis indicated that both the RNA L and RNA M segments of most Korean isolates might have originated in Western Europe and North America but that the RNA S segments for all Korean isolates might have originated in China and Japan. Recombination analysis identified a total of 12 recombination events among all isolates and segments and five recombination events among the 13 Korea isolates; among the five recombinants from Korea, three contained the whole RNA L segment, suggesting reassortment rather than recombination. Our analyses provide evidence that both recombination and reassortment have contributed to the molecular diversity of TSWV.

  15. Retroviral Vectors for Analysis of Viral Mutagenesis and Recombination

    Directory of Open Access Journals (Sweden)

    Jonathan M.O. Rawson

    2014-09-01

    Full Text Available Retrovirus population diversity within infected hosts is commonly high due in part to elevated rates of replication, mutation, and recombination. This high genetic diversity often complicates the development of effective diagnostics, vaccines, and antiviral drugs. This review highlights the diverse vectors and approaches that have been used to examine mutation and recombination in retroviruses. Retroviral vectors for these purposes can broadly be divided into two categories: those that utilize reporter genes as mutation or recombination targets and those that utilize viral genes as targets of mutation or recombination. Reporter gene vectors greatly facilitate the detection, quantification, and characterization of mutants and/or recombinants, but may not fully recapitulate the patterns of mutagenesis or recombination observed in native viral gene sequences. In contrast, the detection of mutations or recombination events directly in viral genes is more biologically relevant but also typically more challenging and inefficient. We will highlight the advantages and disadvantages of the various vectors and approaches used as well as propose ways in which they could be improved.

  16. Retroviral vectors for analysis of viral mutagenesis and recombination.

    Science.gov (United States)

    Rawson, Jonathan M O; Mansky, Louis M

    2014-09-24

    Retrovirus population diversity within infected hosts is commonly high due in part to elevated rates of replication, mutation, and recombination. This high genetic diversity often complicates the development of effective diagnostics, vaccines, and antiviral drugs. This review highlights the diverse vectors and approaches that have been used to examine mutation and recombination in retroviruses. Retroviral vectors for these purposes can broadly be divided into two categories: those that utilize reporter genes as mutation or recombination targets and those that utilize viral genes as targets of mutation or recombination. Reporter gene vectors greatly facilitate the detection, quantification, and characterization of mutants and/or recombinants, but may not fully recapitulate the patterns of mutagenesis or recombination observed in native viral gene sequences. In contrast, the detection of mutations or recombination events directly in viral genes is more biologically relevant but also typically more challenging and inefficient. We will highlight the advantages and disadvantages of the various vectors and approaches used as well as propose ways in which they could be improved.

  17. The influence of recombination on human genetic diversity.

    Directory of Open Access Journals (Sweden)

    Chris C A Spencer

    2006-09-01

    Full Text Available In humans, the rate of recombination, as measured on the megabase scale, is positively associated with the level of genetic variation, as measured at the genic scale. Despite considerable debate, it is not clear whether these factors are causally linked or, if they are, whether this is driven by the repeated action of adaptive evolution or molecular processes such as double-strand break formation and mismatch repair. We introduce three innovations to the analysis of recombination and diversity: fine-scale genetic maps estimated from genotype experiments that identify recombination hotspots at the kilobase scale, analysis of an entire human chromosome, and the use of wavelet techniques to identify correlations acting at different scales. We show that recombination influences genetic diversity only at the level of recombination hotspots. Hotspots are also associated with local increases in GC content and the relative frequency of GC-increasing mutations but have no effect on substitution rates. Broad-scale association between recombination and diversity is explained through covariance of both factors with base composition. To our knowledge, these results are the first evidence of a direct and local influence of recombination hotspots on genetic variation and the fate of individual mutations. However, that hotspots have no influence on substitution rates suggests that they are too ephemeral on an evolutionary time scale to have a strong influence on broader scale patterns of base composition and long-term molecular evolution.

  18. Numerical Study of Passive Catalytic Recombiner for Hydrogen Mitigation

    Directory of Open Access Journals (Sweden)

    Pavan K Sharma

    2010-10-01

    Full Text Available A significant amount of hydrogen is expected to be released within the containment of a water cooled power reactor after a severe accident. To reduce the risk of deflagration/detonation various means for hydrogen control have been adopted all over the world. Passive catalytic recombiner with vertical flat catalytic plate is one of such hydrogen mitigating device. Passive catalytic recombiners are designed for the removal of hydrogen generated in order to limit the impact of possible hydrogen combustion. Inside a passive catalytic recombiner, numerous thin steel sheets coated with catalyst material are vertically arranged at the bottom opening of a sheet metal housing forming parallel flow channels for the surrounding gas atmosphere. Already below conventional flammability limits, hydrogen and oxygen react exothermally on the catalytic surfaces forming harmless steam. Detailed numerical simulations and experiments are required for an in-depth knowledge of such plate type catalytic recombiners. Specific finite volume based in-house CFD code has been developed to model and analyse the working of these recombiner. The code has been used to simulate the recombiner device used in the Gx-test series of Battelle-Model Containment (B-MC experiments. The present paper briefly describes the working principle of such passive catalytic recombiner and salient feature of the CFD model developed at Bhabha Atomic Research Centre (BARC. Finally results of the calculations and comparison with existing data are discussed.

  19. The Contribution of Genetic Recombination to CRISPR Array Evolution.

    Science.gov (United States)

    Kupczok, Anne; Landan, Giddy; Dagan, Tal

    2015-06-16

    CRISPR (clustered regularly interspaced short palindromic repeats) is a microbial immune system against foreign DNA. Recognition sequences (spacers) encoded within the CRISPR array mediate the immune reaction in a sequence-specific manner. The known mechanisms for the evolution of CRISPR arrays include spacer acquisition from foreign DNA elements at the time of invasion and array erosion through spacer deletion. Here, we consider the contribution of genetic recombination between homologous CRISPR arrays to the evolution of spacer repertoire. Acquisition of spacers from exogenic arrays via recombination may confer the recipient with immunity against unencountered antagonists. For this purpose, we develop a novel method for the detection of recombination in CRISPR arrays by modeling the spacer order in arrays from multiple strains from the same species. Because the evolutionary signal of spacer recombination may be similar to that of pervasive spacer deletions or independent spacer acquisition, our method entails a robustness analysis of the recombination inference by a statistical comparison to resampled and perturbed data sets. We analyze CRISPR data sets from four bacterial species: two Gammaproteobacteria species harboring CRISPR type I and two Streptococcus species harboring CRISPR type II loci. We find that CRISPR array evolution in Escherichia coli and Streptococcus agalactiae can be explained solely by vertical inheritance and differential spacer deletion. In Pseudomonas aeruginosa, we find an excess of single spacers potentially incorporated into the CRISPR locus during independent acquisition events. In Streptococcus thermophilus, evidence for spacer acquisition by recombination is present in 5 out of 70 strains. Genetic recombination has been proposed to accelerate adaptation by combining beneficial mutations that arose in independent lineages. However, for most species under study, we find that CRISPR evolution is shaped mainly by spacer acquisition and

  20. Recombination characteristics of therapeutic ion beams on ion chamber dosimetry

    Science.gov (United States)

    Matsufuji, Naruhiro; Matsuyama, Tetsuharu; Sato, Shinji; Kohno, Toshiyuki

    2016-09-01

    In heavy ion radiotherapy, ionization chambers are regarded as a standard for determining the absorbed dose given to patients. In ion dosimetry, it is necessary to correct the radiation quality, which depends on the initial recombination effect. This study reveals for the radiation quality dependence of the initial recombination in air in ion dosimetry. Ionization charge was measured for the beams of protons at 40-160 MeV, carbon at 21-400 MeV/n, and iron at 23.5-500 MeV/n using two identical parallel-plate ionization chambers placed in series along the beam axis. The downstream chamber was used as a monitor operated with a constant applied voltage, while the other chamber was used for recombination measurement by changing the voltage. The ratio of the ionization charge measured by the two ionization chambers showed a linear relationship with the inverse of the voltage in the high-voltage region. The initial recombination factor was estimated by extrapolating the obtained linear relationship to infinite voltage. The extent of the initial recombination was found to increase with decreasing incident energy or increasing atomic number of the beam. This behavior can be explained with an amorphous track structure model: the increase of ionization density in the core region of the track due to decreasing kinetic energy or increasing atomic number leads to denser initial ion production and results in a higher recombination probability. For therapeutic carbon ion beams, the extent of the initial recombination was not constant but changed by 0.6% even in the target region. This tendency was quantitatively well reproduced with the track-structure based on the initial recombination model; however, the transitional change in the track structure is considered to play an important role in further understanding of the characteristics of the initial recombination.

  1. ACG: rapid inference of population history from recombining nucleotide sequences

    Directory of Open Access Journals (Sweden)

    O'Fallon Brendan D

    2013-02-01

    Full Text Available Abstract Background Reconstruction of population history from genetic data often requires Monte Carlo integration over the genealogy of the samples. Among tools that perform such computations, few are able to consider genetic histories including recombination events, precluding their use on most alignments of nuclear DNA. Explicit consideration of recombinations requires modeling the history of the sequences with an Ancestral Recombination Graph (ARG in place of a simple tree, which presents significant computational challenges. Results ACG is an extensible desktop application that uses a Bayesian Markov chain Monte Carlo procedure to estimate the posterior likelihood of an evolutionary model conditional on an alignment of genetic data. The ancestry of the sequences is represented by an ARG, which is estimated from the data with other model parameters. Importantly, ACG computes the full, Felsenstein likelihood of the ARG, not a pairwise or composite likelihood. Several strategies are used to speed computations, and ACG is roughly 100x faster than a similar, recombination-aware program. Conclusions Modeling the ancestry of the sequences with an ARG allows ACG to estimate the evolutionary history of recombining nucleotide sequences. ACG can accurately estimate the posterior distribution of population parameters such as the (scaled population size and recombination rate, as well as many aspects of the recombinant history, including the positions of recombination breakpoints, the distribution of time to most recent common ancestor along the sequence, and the non-recombining trees at individual sites. Multiple substitution models and population size models are provided. ACG also provides a richly informative graphical interface that allows users to view the evolution of model parameters and likelihoods in real time.

  2. Recombinant phage probes for Listeria monocytogenes

    International Nuclear Information System (INIS)

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 104 cells ml-1. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products

  3. Recombinant phage probes for Listeria monocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Carnazza, S; Gioffre, G; Felici, F; Guglielmino, S [Department of Microbiological, Genetic and Molecular Sciences, University of Messina, Messina (Italy)

    2007-10-03

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 10{sup 4} cells ml{sup -1}. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  4. Therapeutic Use of Native and Recombinant Enteroviruses.

    Science.gov (United States)

    Ylä-Pelto, Jani; Tripathi, Lav; Susi, Petri

    2016-03-01

    Research on human enteroviruses has resulted in the identification of more than 100 enterovirus types, which use more than 10 protein receptors and/or attachment factors required in cell binding and initiation of the replication cycle. Many of these "viral" receptors are overexpressed in cancer cells. Receptor binding and the ability to replicate in specific target cells define the tropism and pathogenesis of enterovirus types, because cellular infection often results in cytolytic response, i.e., disruption of the cells. Viral tropism and cytolytic properties thus make native enteroviruses prime candidates for oncolytic virotherapy. Copy DNA cloning and modification of enterovirus genomes have resulted in the generation of enterovirus vectors with properties that are useful in therapy or in vaccine trials where foreign antigenic epitopes are expressed from or on the surface of the vector virus. The small genome size and compact particle structure, however, set limits to enterovirus genome modifications. This review focuses on the therapeutic use of native and recombinant enteroviruses and the methods that have been applied to modify enterovirus genomes for therapy. PMID:26907330

  5. Dielectronic recombination of Co-like tantalum

    Institute of Scientific and Technical Information of China (English)

    Zhou Li; Meng Fan-Chang; Huang Min; Chen Chong-Yang; Wang Yan-Sen

    2009-01-01

    Abinitio calculation of the total dielectronic recombination (DR) rate coefficient from the ground state of Colike tantalum is performed using the relativistic distorted-wave approximation with configuration interaction. The contributions to the total DR rate coefficients are explicitly calculated from the complexes of Ni-like tantalum:3s23p63d3/233d5/26n'l',3s23p53d10n'l',3s3p63d10n'l',3s23p63d84ln'l',3s23p53d94ln'l' and 3s3p63d94ln'l' with n'≤25,and 3s23p63d85ln'l' with n'≤9.The l' and n' dependences of partial DR rate coefficients are investigated.The contributions from higher n'complexes are evaluated by a level-by-level extrapolation method.The total DR rate coefficients mainly come from the complex series 3s23p63d84ln'l',3s23pS3d94ln'l' and are fitted to an empirical formula with high accuracy.Comparison of the present results with those of other works shows that the previously published data underestimate significantly the DR rates of Co-like tantalum.

  6. Coacervate microspheres as carriers of recombinant adenoviruses.

    Science.gov (United States)

    Kalyanasundaram, S; Feinstein, S; Nicholson, J P; Leong, K W; Garver, R I

    1999-01-01

    The therapeutic utility of recombinant adenoviruses (rAds) is limited in part by difficulties in directing the viruses to specific sites and by the requirement for bolus administration, both of which limit the efficiency of target tissue infection. As a first step toward overcoming these limitations, rAds were encapsulated in coacervate microspheres comprised of gelatin and alginate followed by stabilization with calcium ions. Ultrastructural evaluation showed that the microspheres formed in this manner were 0.8-10 microM in diameter, with viruses evenly distributed. The microspheres achieved a sustained release of adenovirus with a nominal loss of bioactivity. The pattern of release and the total amount of virus released was modified by changes in microsphere formulation. Administration of the adenovirus-containing microspheres to human tumor nodules engrafted in mice showed that the viral transgene was transferred to the tumor cells. It is concluded that coacervate microspheres can be used to encapsulate bioactive rAd and release it in a time-dependent manner.

  7. Dielectronic Recombination In Active Galactic Nuclei

    Science.gov (United States)

    Lukic, D. V.; Schnell, M.; Savin, D. W.; Altun, Z.; Badnell, N.; Brandau, C.; Schmidt, E. W.; Mueller, A.; Schippers, S.; Sprenger, F.; Lestinsky, M.; Wolf, A.

    2006-01-01

    XMM-Newton and Chandra observations of active galactic nuclei (AGN) show rich spectra of X-ray absorption lines. These observations have detected a broad unresolved transition array (UTA) between approx. 15-17 A. This is attributed to inner-shell photoexcitation of M-shell iron ions. Modeling these UTA features is currently limited by uncertainties in the low-temperature dielectronic recombination (DR) data for M-shell iron. In order to resolve this issue, and to provide reliable iron M-shell DR data for plasma modeling, we are carrying out a series of laboratory measurements using the heavy-ion Test Storage Ring (TSR) at the Max-Plank-Institute for Nuclear Physics in Heidelberg, Germany. Currently, laboratory measurements of low temperature DR can only be performed at storage rings. We use the DR data obtained at TSR, to calculate rate coefficients for plasma modeling and to benchmark theoretical DR calculations. Here we report our recent experimental results for DR of Fe XIV forming Fe XIII.

  8. Therapeutic Use of Native and Recombinant Enteroviruses.

    Science.gov (United States)

    Ylä-Pelto, Jani; Tripathi, Lav; Susi, Petri

    2016-02-23

    Research on human enteroviruses has resulted in the identification of more than 100 enterovirus types, which use more than 10 protein receptors and/or attachment factors required in cell binding and initiation of the replication cycle. Many of these "viral" receptors are overexpressed in cancer cells. Receptor binding and the ability to replicate in specific target cells define the tropism and pathogenesis of enterovirus types, because cellular infection often results in cytolytic response, i.e., disruption of the cells. Viral tropism and cytolytic properties thus make native enteroviruses prime candidates for oncolytic virotherapy. Copy DNA cloning and modification of enterovirus genomes have resulted in the generation of enterovirus vectors with properties that are useful in therapy or in vaccine trials where foreign antigenic epitopes are expressed from or on the surface of the vector virus. The small genome size and compact particle structure, however, set limits to enterovirus genome modifications. This review focuses on the therapeutic use of native and recombinant enteroviruses and the methods that have been applied to modify enterovirus genomes for therapy.

  9. Therapeutic Use of Native and Recombinant Enteroviruses

    Directory of Open Access Journals (Sweden)

    Jani Ylä-Pelto

    2016-02-01

    Full Text Available Research on human enteroviruses has resulted in the identification of more than 100 enterovirus types, which use more than 10 protein receptors and/or attachment factors required in cell binding and initiation of the replication cycle. Many of these “viral” receptors are overexpressed in cancer cells. Receptor binding and the ability to replicate in specific target cells define the tropism and pathogenesis of enterovirus types, because cellular infection often results in cytolytic response, i.e., disruption of the cells. Viral tropism and cytolytic properties thus make native enteroviruses prime candidates for oncolytic virotherapy. Copy DNA cloning and modification of enterovirus genomes have resulted in the generation of enterovirus vectors with properties that are useful in therapy or in vaccine trials where foreign antigenic epitopes are expressed from or on the surface of the vector virus. The small genome size and compact particle structure, however, set limits to enterovirus genome modifications. This review focuses on the therapeutic use of native and recombinant enteroviruses and the methods that have been applied to modify enterovirus genomes for therapy.

  10. Consistency and stability of recombinant fermentations.

    Science.gov (United States)

    Wiebe, M E; Builder, S E

    1994-01-01

    Production of proteins of consistent quality in heterologous, genetically-engineered expression systems is dependent upon identifying the manufacturing process parameters which have an impact on product structure, function, or purity, validating acceptable ranges for these variables, and performing the manufacturing process as specified. One of the factors which may affect product consistency is genetic instability of the primary product sequence, as well as instability of genes which code for proteins responsible for post-translational modification of the product. Approaches have been developed for mammalian expression systems to assure that product quality is not changing through mechanisms of genetic instability. Sensitive protein analytical methods, particularly peptide mapping, are used to evaluate product structure directly, and are more sensitive in detecting genetic instability than is direct genetic analysis by nucleotide sequencing of the recombinant gene or mRNA. These methods are being employed to demonstrate that the manufacturing process consistently yields a product of defined structure from cells cultured through the range of cell ages used in the manufacturing process and well beyond the maximum cell age defined for the process. The combination of well designed validation studies which demonstrate consistent product quality as a function of cell age, and rigorous quality control of every product lot by sensitive protein analytical methods provide the necessary assurance that product structure is not being altered through mechanisms of mutation and selection.

  11. Developing recombinant antibodies for biomarker detection

    Energy Technology Data Exchange (ETDEWEB)

    Baird, Cheryl L.; Fischer, Christopher J.; Pefaur, Noah B.; Miller, Keith D.; Kagen, Jacob; Srivastava, Sudhir; Rodland, Karin D.

    2010-10-01

    Monoclonal antibodies (mAbs) have an essential role in biomarker validation and diagnostic assays. A barrier to pursuing these applications is the reliance on immunization and hybridomas to produce mAbs, which is time-consuming and may not yield the desired mAb. We recommend a process flow for affinity reagent production that utilizes combinatorial protein display systems (eg, yeast surface display or phage display) rather than hybridomas. These systems link a selectable phenotype-binding conferred by an antibody fragment-with a means for recovering the encoding gene. Recombinant libraries obtained from immunizations can produce high-affinity antibodies (<10 nM) more quickly than other methods. Non-immune libraries provide an alternate route when immunizations are not possible, or when suitable mAbs are not recovered from an immune library. Directed molecular evolution (DME) is an integral part of optimizing mAbs obtained from combinatorial protein display, but can also be used on hybridoma-derived mAbs. Variants can easily be obtained and screened to increase the affinity of the parent mAb (affinity maturation). We discuss examples where DME has been used to tailor affinity reagents to specific applications. Combinatorial protein display also provides an accessible method for identifying antibody pairs, which are necessary for sandwich-type diagnostic assays.

  12. Recombinant Enzyme Replacement Therapy in Hypophosphatasia.

    Science.gov (United States)

    Hofmann, Christine; Jakob, Franz; Seefried, Lothar; Mentrup, Birgit; Graser, Stephanie; Plotkin, Horacio; Girschick, Hermann J; Liese, Johannes

    2015-01-01

    Hypophosphatasia (HPP) is a rare monogenetic and multisystemic disease with involvement of different organs, including bone, muscle, kidney, lung, gastrointestinal tract and the nervous system. The exact metabolic mechanisms of the effects of TNAP deficiency in different tissues are not understood in detail. There is no approved specific treatment for HPP; therefore symptomatic treatment in order to improve the clinical features is of major interest. Enzyme replacement therapy (ERT) is a relatively new type of treatment based on the principle of administering a medical treatment replacing a defective or absent enzyme. Recently ERT with a bone targeted recombinant human TNAP molecule has been reported to be efficient in ten severely affected patients and improved survival of life threatening forms. These results are very promising especially with regard to the skeletal phenotype but it is unclear whether ERT also has beneficial effects for craniosynostosis and in other affected tissues in HPP such as brain and kidney. Long-term data are not yet available and further systematic clinical trials are needed. It is also necessary to establish therapeutic approaches to help patients who are affected by less severe forms of HPP but also suffer from a significant reduction in quality of life. Further basic research on TNAP function and role in different tissues and on its physiological substrates is critical to gain a better insight in the pathogenesis in HPP. This and further experiences in new therapeutic strategies may improve the prognosis and quality of life of patients with all forms of HPP.

  13. Development of recombinant vaccines for botulinum neurotoxin.

    Science.gov (United States)

    Smith, L A

    1998-11-01

    Synthetic genes encoding non-toxic, carboxyl-terminal regions (approximately 50 kDa) of botulinum neurotoxin (BoNT) serotypes A and B (referred to as fragment C or HC) were constructed and cloned into the methylotropic yeast, Pichia pastoris. Genes specifying BoNTA(HC) and BoNTB(HC) were expressed as both intracellular and secreted products. Recombinants, expressed intracellularly, yielded products with the expected molecular weight as judged by SDS PAGE and Western blot (immunoblot) analysis, while secreted products were larger due to glycosylation. Gene products were used to vaccinate mice and evaluated for their ability to elicit protective antibody titers in vivo. Mice given three intramuscular vaccinations with yeast supernatant containing glycosylated BoNTA(HC) were protected against an intraperitoneal challenge of 10(6) 50% mouse lethal doses (MLD50) of serotype A neurotoxin, a result not duplicated by its BoNTB(HC) counterpart. Vaccinating mice with cytoplasmically produced BoNTA(HC) and BoNTB(HC) protected animals from a challenge of 10(6) MLD50 of serotype A and B toxins, respectively. Because of the glycosylation encountered with secreted BoNT(HC), our efforts focused on the production and purification of products from intracellular expression. PMID:9792170

  14. Recombinant phage probes for Listeria monocytogenes

    Science.gov (United States)

    Carnazza, S.; Gioffrè, G.; Felici, F.; Guglielmino, S.

    2007-10-01

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 104 cells ml-1. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  15. Sequence and recombination analyses of the geminivirus replication initiator protein

    Indian Academy of Sciences (India)

    T Vadivukarasi; K R Girish; R Usha

    2007-01-01

    The sequence motifs present in the replication initiator protein (Rep) of geminiviruses have been compared with those present in all known rolling circle replication initiators. The predicted secondary structures of Rep representing each group of organisms have been compared and found to be conserved. Regions of recombination in the Rep gene and the adjoining 5′ intergenic region (IR) of representative species of Geminiviridae have been identified using Recombination Detection Programs. The possible implications of such recombinations on the increasing host range of geminivirus infections are discussed.

  16. Recombinative generalization of subword units using matching to sample.

    LENUS (Irish Health Repository)

    Mahon, Catherine

    2010-01-01

    The purpose of the current study was to develop and test a computerized matching-to-sample (MTS) protocol to facilitate recombinative generalization of subword units (onsets and rimes) and recognition of novel onset-rime and onset-rime-rime words. In addition, we sought to isolate the key training components necessary for recombinative generalization. Twenty-five literate adults participated. Conditional discrimination training emerged as a crucial training component. These findings support the effectiveness of MTS in facilitating recombinative generalization, particularly when conditional discrimination training with subword units is used.

  17. Stimulated radiative recombination of H{sup +} and He {sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Rogelstad, M.L.; Mitchell, J.B.A. [Western Ontario Univ., Physics Dept., London, ON (Canada); Yousif, F.B. [UNAM, Inst. de Fisica, Cuernavaca (Mexico); Morgan, T.J. [Wesleyan Univ., Physics Dept., Middletown, CT (United States)

    1997-09-14

    Stimulated radiative recombination has been demonstrated experimentally in e{sup -}+H{sup +} and e{sup -} + He{sup +} collisions using a merged electron-ion beams apparatus with field ionization detection of the excited neutral products. Enhancement of the recombination over spontaneous recombination to form the n = 11, 12 and 13 levels of atomic hydrogen and the n = 11 and 12 levels of atomic helium by factors of between 1000 and 3000 have been found using a CO{sub 2} laser power of 8 W. Evidence for the resolution of fine-structure levels has been seen for the case of helium. (author).

  18. Dynamics of carrier recombination in a semiconductor laser structure

    Energy Technology Data Exchange (ETDEWEB)

    Dzhioev, R. I., E-mail: dzhioev@orient.ioffe.ru; Kavokin, K. V.; Kusrayev, Yu. G.; Poletaev, N. K. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2015-11-15

    Carrier-recombination dynamics is studied by the method of optical orientation at room temperature in the active layer of a laser diode structure. The dependence of the degree of electron-spin orientation on the excitation density is attributed to saturation of the nonradiative-recombination channel. The time of electron capture at recombination centers is determined to be τ{sub e} = 5 × 10{sup –9} s. The temperature of nonequilibrium electrons heated by a He–Ne laser is estimated.

  19. RecQ Promotes Toxic Recombination in Cells Lacking Recombination-Intermediate-Removal Proteins

    OpenAIRE

    Magner, Daniel B.; Blankschien, Matthew D.; Lee, Jennifer A.; Pennington, Jeanine M.; James R. Lupski; Rosenberg, Susan M.

    2007-01-01

    The RecQ-helicase family is widespread, highly conserved, and includes human orthologues that suppress genomic instability and cancer. In vivo, some RecQ homologues promote reduction of steady-state levels of bimolecular recombination intermediates (BRIs), which block chromosome segregation if not resolved. We find that in vivo, E. coli RecQ can promote the opposite: the net accumulation of BRIs. We report that cells lacking Ruv and UvrD BRI-resolution and -prevention proteins die and display...

  20. Nonradiative recombination of excitons in semimagnetic quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Chernenko, A. V., E-mail: chernen@issp.ac.ru [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation)

    2015-12-15

    The mechanisms of the nonradiative recombination of excitons in neutral and charged quantum dots based on II–VI semimagnetic semiconductors are investigated. It is shown that, along with the dipole–dipole and direct-exchange mechanisms, there is one more mechanism referred to as the indirect-exchange mechanism and related to sp–d mixing. The selection rules for nonradiative recombination by exchange mechanisms are subsequently derived. The dependence of the efficiency of all recombination mechanisms on the quantum-dot size is studied. The experimentally observed growth in the intracenter photoluminescence intensity with decreasing size of dots and nanocrystals is accounted for. Methods for experimental determination of the contributions of different mechanisms to nonradiative recombination are discussed.

  1. Expression and purification of soluble recombinant Hexastatin in E. coli

    International Nuclear Information System (INIS)

    Purpose: To construct the expression vector of Hexastatin gene, to express and to purify the recombinant protein for further activity research. Methods: The human Hexastatin gene was isolated by RTPCR from EC9706 cells total RNA and cloned into pMD18-T for sequencing. Then the Hexastatin gene was subcloned into pMAL-c4x expression vector and induced to express by IPTG. The recombinant fusion protein was purified with Amylose Resin Heads. Results: RT-PCR product was about 687 bp and its sequence was the same as that of Hexastatin reported. The recombinant protein was expressed in E. coli BL21 with high level and the soluble protein accounted for 24.8% of the total bacterial protein. The purification of recombinant protein purified with Amylose Resin Heads reached more than 90%. Conclusion: The cloning, expression and purification of human Hexastatin have laid a foundation for its anti-angiogenesis therapy for tumor. (authors)

  2. Non-Enzymatic Template-Directed Recombination of RNAs

    Directory of Open Access Journals (Sweden)

    Marina A. Zenkova

    2009-04-01

    Full Text Available RNA non-enzymatic recombination reactions are of great interest within the hypothesis of the "RNA world", which argues that at some stage of prebiotic life development proteins were not yet engaged in biochemical reactions and RNA carried out both the information storage task and the full range of catalytic roles necessary in primitive self-replicating systems. Here we report on the study of recombination reaction occuring between two 96 nucleotides (nts fragments of RNAs under physiological conditions and governed by a short oligodeoxyribonucleotide template, partially complementary to sequences within each of the RNAs. Analysis of recombination products shows that ligation is predominantly template-directed, and occurs within the complementary complex with the template in "butt-to-butt" manner, in 1- or 3- nts bulges or in 2-3 nts internal loops. Minor recombination products formed in the template-independent manner are detected as well.

  3. Rate coefficients for N2(+)(v) dissociative recombination

    Science.gov (United States)

    Bates, D. R.; Mitchell, J. B. A.

    1991-09-01

    The data of Zipf (1980) on N2(+)(v) dissociative recombination are analyzed taking into account the fact that there is coupling due to reversible symmetrical resonance charge transfer, N2(+)(v) + N2(0) yields N2(+)(0) + N2(v). The vibrational deactivation in N2(+)(v)-Ne collisions is also considered. A reported experimental value of the vibrational deactivation coefficient is found to be much higher than can be reconciled with the results of Zipf and it is therefore rejected. The analysis shows that the recombination coefficient for N2(+)(0) is about 2.6 x 10 exp-7 cu cm/s at 300 K and that recombination coefficients for N2(+)(1) and N2(+)(2) are substantially smaller. It is concluded that these coefficients conflict with the dissociative recombination cross section vs energy curve obtained by the merged beam method.

  4. Phylogeny and Homologous Recombination in Japanese Encephalitis Viruses

    Institute of Scientific and Technical Information of China (English)

    Li Xiao-xue; Cong Ying-ying; Wang Xin; Ren Yu-dong; Ren Xiao-feng; Lu Ai-guo; Li Guang-xing

    2015-01-01

    Japanese encephalitis virus (JEV) is a significant causative agent of arthropod-borne encephalitis and what is less clear that the factors cause the virus wide spread. The objective was to confirm whether the homologous recombination imposed on JEV. The phylogenetic and homologous recombination analyses were performed based on 163 complete JEV genomes which were recently isolated. They were still separated into five genotypes (GI-GV) and the most of recently isolated JEVs were GI rather than GIII in Asian areas including mainland China. Two recombinant events were identified in JEV and the evidence of the recombination was observed between China and Japan isolates that partitioned into two distinct subclades, but still the same genotype (GIII). Our data further suggested that most of the nucleotides in JEV genome were under negative selection; however, changes within codon 2 316 (amino acid NS4b-44) showed an evidence of the positive selection.

  5. Distant Recombination and the Creation of Basic Inventions

    DEFF Research Database (Denmark)

    Barirani, Ahmad; Beaudry, Catherine; Agard, Bruno

    2015-01-01

    This article explores whether the relationship between the breath of technological integration (recombination distance) and the breath of an invention׳s subsequent application (basicness) is moderated by the sector of activity (private or public), science-linkage strength and industry......; increasing reliance upon basic science moderates the relationship between recombination distance and basicness; and increases to recombination distance in emerging science-based industries increases invention basicness at a higher rate. These findings have implications regarding the debate around...... characteristics. Our analysis of Canadian nanotechnology patents granted between 1990 and 1997 shows that although private organizations generally yield smaller rates of basic inventions than public organizations, increases to recombination distance by the former increases invention basicness at a higher rate...

  6. Purification of recombinant ovalbumin from inclusion bodies of Escherichia coli.

    Science.gov (United States)

    Upadhyay, Vaibhav; Singh, Anupam; Panda, Amulya K

    2016-01-01

    Recombinant ovalbumin expressed in bacterial host is essentially free from post-translational modifications and can be useful in understanding the structure-function relationship of the protein. In this study, ovalbumin was expressed in Escherichia coli in the form of inclusion bodies. Ovalbumin inclusion bodies were solubilized using urea and refolded by decreasing the urea concentration by dilution. Refolded protein was purified by anion exchange chromatography. Overall recovery of purified recombinant ovalbumin from inclusion bodies was about 30% with 98% purity. Purified recombinant ovalbumin was characterized by mass spectrometry, circular dichroism and fluorescence spectroscopy. Recombinant ovalbumin was shown to be resistant to trypsin using protease resistance assay. This indicated proper refolding of ovalbumin from inclusion bodies of E. coli. This method provides a simple way of producing ovalbumin free of post-translational modifications.

  7. Meiotic recombination in normal and cloned bulls and their offspring

    Science.gov (United States)

    Homologous chromosome pairing and recombination are essential components of meiosis and sexual reproduction. The reshuffling of genetic material through breakage and reunion of chromatids ensure proper segregation of homologous chromosomes in reduction division and genetic diversity in the progeny....

  8. The evolutionary value of recombination is constrained by genome modularity.

    Directory of Open Access Journals (Sweden)

    Darren P Martin

    2005-10-01

    Full Text Available Genetic recombination is a fundamental evolutionary mechanism promoting biological adaptation. Using engineered recombinants of the small single-stranded DNA plant virus, Maize streak virus (MSV, we experimentally demonstrate that fragments of genetic material only function optimally if they reside within genomes similar to those in which they evolved. The degree of similarity necessary for optimal functionality is correlated with the complexity of intragenomic interaction networks within which genome fragments must function. There is a striking correlation between our experimental results and the types of MSV recombinants that are detectable in nature, indicating that obligatory maintenance of intragenome interaction networks strongly constrains the evolutionary value of recombination for this virus and probably for genomes in general.

  9. The Evolutionary Value of Recombination Is Constrained by Genome Modularity.

    Directory of Open Access Journals (Sweden)

    2005-10-01

    Full Text Available Genetic recombination is a fundamental evolutionary mechanism promoting biological adaptation. Using engineered recombinants of the small single-stranded DNA plant virus, Maize streak virus (MSV, we experimentally demonstrate that fragments of genetic material only function optimally if they reside within genomes similar to those in which they evolved. The degree of similarity necessary for optimal functionality is correlated with the complexity of intragenomic interaction networks within which genome fragments must function. There is a striking correlation between our experimental results and the types of MSV recombinants that are detectable in nature, indicating that obligatory maintenance of intragenome interaction networks strongly constrains the evolutionary value of recombination for this virus and probably for genomes in general.

  10. Secretion expression of recombinant glucagon in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel approach for the preparation of recombinant human glucagon was described. An expression vector pAGluT, containing phoA promoter, phoA signal peptide and glucagon gene, was constructed by means of genetic engineering. Escherichia coli strain YK537 was transformed with pAGluT. High-level secretory expression of recombinant human glucagon was achieved. The expression yield of recombinant human glucagon was found to be 80 mg/L, approximately 30% of the total proteins in supernatant. The biological activities and the physicochemical properties of the purified recombinant human glucagon were found to be the same as that of native glucagon. In addition, our results suggested that phoA expression system may be suitable for the expression of other small peptides.

  11. Recombination of atomic oxygen and hydrogen on amorphous carbon

    International Nuclear Information System (INIS)

    Deposit buildup and fuel entrapment due to amorphous carbon are relevant issues in fusion devices with carbon based plasma facing components. Neutral atomic species play a significant role – atomic hydrogen facilitates the formation of amorphous carbon while atomic oxygen could be used to remove carbon deposits. The kinetics of either reaction depends on the density of neutral species, which in turn is influenced by recombination on the vessel walls. In this work, we measured the probability of heterogeneous recombination of atomic hydrogen and oxygen on amorphous carbon deposits. The recombination coefficients were determined by observing density profiles of atomic species in a closed side-arm of a plasma vessel with amorphous carbon deposit-lined walls. Density profiles were measured with fiber optics catalytic probes. The source of atomic species was inductively coupled radiofrequency plasma. The measured recombination coefficient values were of the order of 10−3 for both species

  12. Dissociative Recombination of Molecular Ions for Astrochemistry

    Science.gov (United States)

    Novotny, Oldrich; Becker, A.; Buhr, H.; Fleischmann, Andreas; Gamer, Lisa; Geppert, W.; Krantz, C.; Kreckel, H.; Schwalm, D.; Spruck, K.; Wolf, A.; Savin, Daniel Wolf

    2014-06-01

    Dissociative recombination (DR) of molecular ions is a key chemical process in the cold interstellar medium (ISM). DR affects the composition, charge state, and energy balance of such environments. Astrochemical models of the ISM require reliable total DR cross sections as well as knowledge of the chemical composition of the neutral DR products. We have systematically measured DR for many astrophysically relevant molecular ions utilizing the TSR storage ring at the Max-Planck-Institute for Nuclear Physics (MPIK) in Heidelberg, Germany. We used the merged ion-electron beam technique combined with an energy- and position-sensitive imaging detector and are able to study DR down to plasma temperatures as low as 10 K. The DR count rate is used to obtain an absolute merged beams DR rate coefficient from which we can derive a thermal rate coefficient needed for plasma models. Additionally we determine the masses of the DR products by measuring their kinetic energy in the laboratory reference frame. This allows us to assign particular DR fragmentation channels and to obtain their branching ratios. All this information is particularly important for understanding DR of heteronuclear polyatomic ions. We will present DR results for several ions recently investigated at TSR. A new Cryogenic Storage Ring (CSR) is currently being commissioned at MPIK. With the chamber cooled down to ~10 K and a base pressure better than 10-13 mbar, this setup will allow internal cooling of the stored ions down to their rotational ground states, thus opening a new era in DR experiments. New technological challenges arise due to the ultracold, ultra-high vacuum environment of the CSR and thus the detection techniques used at TSR cannot be easily transferred to CSR. We will present new approaches for DR fragment detection in cryogenic environment. This work is supported in part by NASA and the NSF.

  13. Recombinant thrombomodulin for secondary thrombotic thrombocytopenic purpura.

    Science.gov (United States)

    Nakamura, Kensuke; Inokuchi, Ryota; Hiruma, Takahiro; Ohshima, Kazuma; Sonoo, Tomohiro; Tokunaga, Kurato; Doi, Kent; Nakajima, Susumu

    2016-06-01

    In the pathogenesis of thrombotic thrombocytopenic purpura (TTP), reductions in the enzyme activity of ADAMTS13, which cuts ultralarge von Willebrand multimers, generates shear stress on the microvascular endothelium, leading to platelet aggregation and the formation of a thrombus. ADAMTS13 activity is markedly decreased in typical TTP, but is only mildly reduced in secondary TTP, which concomitantly develops with primary disease. The latter develops with septic disseminated intravascular coagulation (DIC) and often causes organ failure. Recombinant thrombomodulin (rTM) is a drug that is used to treat DIC and may also remit TTP because it improves vascular endothelial dysfunction. Therefore, we herein investigated the efficacy of rTM in patients treated for the pathology of secondary TTP. Patients who were admitted to the Emergency and Critical Care Center of our hospital and met the following conditions were extracted and retrospectively analyzed: hemolytic anemia accompanied by fragmented red blood cells (Hb TTP, significantly increased in the rTM treatment group: 3.3 ± 2.6→11.3 ± 14.6 versus 3.5 ± 3.7→5.7 ± 3.9 (×1000/μL) (P = 0.034). Thrombotic thrombocytopenic purpura originally requires invasive treatments and its prognosis is not favorable. Blood thrombomodulin levels also markedly increase due to vascular endothelial dysfunction, whereas rTM alleviates vascular endothelial dysfunction in TTP patients with high blood TM levels, suggesting the importance of administering rTM. Thus, rTM may be effective for secondary TTP and may be adopted as adjuvant therapy. PMID:27310951

  14. A Gateway MultiSite Recombination Cloning Toolkit

    OpenAIRE

    Petersen, Lena K.; Stowers, R. Steven

    2011-01-01

    The generation of DNA constructs is often a rate-limiting step in conducting biological experiments. Recombination cloning of single DNA fragments using the Gateway system provided an advance over traditional restriction enzyme cloning due to increases in efficiency and reliability. Here we introduce a series of entry clones and a destination vector for use in two, three, and four fragment Gateway MultiSite recombination cloning whose advantages include increased flexibility and versatility. ...

  15. DNA Cloning Using In Vitro Site-Specific Recombination

    OpenAIRE

    Hartley, James L.; Temple, Gary F.; Brasch, Michael A.

    2000-01-01

    As a result of numerous genome sequencing projects, large numbers of candidate open reading frames are being identified, many of which have no known function. Analysis of these genes typically involves the transfer of DNA segments into a variety of vector backgrounds for protein expression and functional analysis. We describe a method called recombinational cloning that uses in vitro site-specific recombination to accomplish the directional cloning of PCR products and the subsequent automatic...

  16. E. coli Tarafından Sentezlenen Recombinant Soyacystatinin Karakterizasyonu

    OpenAIRE

    AKPINAR, Özlem; AN, Haejung

    2004-01-01

    Recombinant (r-) soyacystatin was characterized for their inhibitory activity against papain and compared to egg white cystatin. r-Soyacystatin expressed in E. coli was purified 4.33 fold as a recombinant protein with phenyl-Sepharose and DEAE. Egg white cystatin was purified by using affinity chromatography on CM-papain-Sepharose. The specific interaction of r-soyacystatin and papain was detected on isoelectric focusing gel. Papain and r-soyacystatin formed a complex and the complex was res...

  17. Recombinant Protein Production and Insect Cell Culture and Process

    Science.gov (United States)

    Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); OConnor, Kim C. (Inventor); Francis, Karen M. (Inventor); Andrews, Angela D. (Inventor); Prewett, Tracey L. (Inventor)

    1997-01-01

    A process has been developed for recombinant production of selected polypeptides using transformed insect cells cultured in a horizontally rotating culture vessel modulated to create low shear conditions. A metabolically transformed insect cell line is produced using the culture procedure regardless of genetic transformation. The recombinant polypeptide can be produced by an alternative process using virtually infected or stably transformed insect cells containing a gene encoding the described polypeptide. The insect cells can also be a host for viral production.

  18. Green factory: plants as bioproduction platforms for recombinant proteins.

    Science.gov (United States)

    Xu, Jianfeng; Dolan, Maureen C; Medrano, Giuliana; Cramer, Carole L; Weathers, Pamela J

    2012-01-01

    Molecular farming, long considered a promising strategy to produce valuable recombinant proteins not only for human and veterinary medicine, but also for agriculture and industry, now has some commercially available products. Various plant-based production platforms including whole-plants, aquatic plants, plant cell suspensions, and plant tissues (hairy roots) have been compared in terms of their advantages and limits. Effective recombinant strategies are summarized along with descriptions of scalable culture systems and examples of commercial progress and success.

  19. Site-Specific Recombination Strategies for Engineering Actinomycete Genomes

    OpenAIRE

    Herrmann, Simone; Siegl, Theresa; Luzhetska, Marta; Petzke, Lutz; Jilg, Caroline; Welle, Elisabeth; Erb, Annette; Leadlay, Peter F; Bechthold, Andreas; Luzhetskyy, Andriy

    2012-01-01

    The feasibility of using technologies based on site-specific recombination in actinomycetes was shown several years ago. Despite their huge potential, these technologies mostly have been used for simple marker removal from a chromosome. In this paper, we present different site-specific recombination strategies for genome engineering in several actinomycetes belonging to the genera Streptomyces, Micromonospora, and Saccharothrix. Two different systems based on Cre/loxP and Dre/rox have been ut...

  20. The efficacy of recombinant versus urinary HCG in ART outcome

    OpenAIRE

    Maryam Eftekhar; Mohammad Ali Khalili; Elham Rahmani

    2012-01-01

    Background: Human chorionic gonadotropin (HCG) has been used as a replacement for the mid-cycle luteinizing hormone (LH) surge for several years. The recent arrival of recombinant DNA technology has made recombinant HCG (rHCG) accessible. Objective: To assess efficacy of rHCG compared to urinary HCG (uHCG) for triggering of ovulation and induction of final oocyte maturation in assisted reproductive cycles. Materials and Methods: 200 patients who were candidate for ICSI were randomly divided i...

  1. Non-Enzymatic Template-Directed Recombination of RNAs

    OpenAIRE

    Marina A Zenkova; Vlassov, Valentin V.; Alexei V. Lutay; Sergey Y. Nechaev

    2009-01-01

    RNA non-enzymatic recombination reactions are of great interest within the hypothesis of the "RNA world", which argues that at some stage of prebiotic life development proteins were not yet engaged in biochemical reactions and RNA carried out both the information storage task and the full range of catalytic roles necessary in primitive self-replicating systems. Here we report on the study of recombination reaction occuring between two 96 nucleotides (nts) fragments of RNAs under physiological...

  2. ${}^3$H production via neutron-neutron-deuteron recombination

    OpenAIRE

    Deltuva, A; Fonseca, A.C.

    2013-01-01

    We study the recombination of two neutrons and deuteron into neutron and ${}^3$H using realistic nucleon-nucleon potential models. Exact Alt, Grassberger, and Sandhas equations for the four-nucleon transition operators are solved in the momentum-space framework using the complex-energy method with special integration weights. We find that at astrophysical or laboratory neutron densities the production of ${}^3$H via the neutron-neutron-deuteron recombination is much slower as compared to the ...

  3. Experimental observation of laser-stimulated radiative recombination

    International Nuclear Information System (INIS)

    Spontaneous radiative recombination between protons and electrons to form hydrogen atoms with 8≤n≤19 has been measured. CO2 laser light has been shown to induce stimulated radiative recombination to the n=11 and 12 levels with an inferred gain in the cross section of 1720±860 and 4790±2830 for a laser power of 12.6 and 15.3 W, respectively. This is in line with that predicted theoretically

  4. Antierythropoietin Antibodies in Hemodialysis Patients Treated with Recombinant Erythropoietin

    OpenAIRE

    Savaş ÖZTÜRK; Alper GÜMÜŞ; Vecihi MEMİLİ; Muhammet Emin DÜZ; Egemen CEBECİ; Macit KOLDAŞ; Rümeyza KAZANCIOĞLU

    2014-01-01

    OBJECTIVE: Erythropoietin resistance is a serious problem in patients treated with recombinant erythropoietin. Antierythropoietin antibodies are considered to be one of the causes of this resistance. MATERIAL and ME THODS: We investigated antierythropoietin antibodies in chronic hemodialysis patients and compared the results with healthy controls by means of establishing an ELISA method. A total of 121 chronic hemodialysis patients receiving recombinant erythropoietin were included in the ...

  5. Amifostine Metabolite WR-1065 Disrupts Homologous Recombination in Mammalian Cells

    OpenAIRE

    Dziegielewski, Jaroslaw; Goetz, Wilfried; Murley, Jeffrey S.; David J Grdina; Morgan, William F.; Janet E. Baulch

    2010-01-01

    Repair of DNA damage through homologous recombination (HR) pathways plays a crucial role in maintaining genome stability. However, overstimulation of HR pathways in response to genotoxic stress may abnormally elevate recombination frequencies, leading to increased mutation rates and delayed genomic instability. Radiation-induced genomic instability has been detected after exposure to both low- and high-linear energy transfer (LET) radiations, but the mechanisms responsible for initiating or p...

  6. Green factory: plants as bioproduction platforms for recombinant proteins.

    Science.gov (United States)

    Xu, Jianfeng; Dolan, Maureen C; Medrano, Giuliana; Cramer, Carole L; Weathers, Pamela J

    2012-01-01

    Molecular farming, long considered a promising strategy to produce valuable recombinant proteins not only for human and veterinary medicine, but also for agriculture and industry, now has some commercially available products. Various plant-based production platforms including whole-plants, aquatic plants, plant cell suspensions, and plant tissues (hairy roots) have been compared in terms of their advantages and limits. Effective recombinant strategies are summarized along with descriptions of scalable culture systems and examples of commercial progress and success. PMID:21924345

  7. Recombination Lines of CII in the Spectra of Planetary Nebulae

    OpenAIRE

    Sochi, Taha

    2010-01-01

    The current report presents the work to investigate the recombination lines of CII in the spectra of planetary nebulae. Two CIII targets were prepared and used to generate theoretical data required in the investigation of recombination lines that arise from collisions between electrons and ions in thin plasma found in planetary nebulae and other astrophysical objects. One of these targets contains 9 atomic terms while the other contains 26 terms. For each one of these targets, theoretical dat...

  8. Historical Perspectives Pertaining to the NIH Recombinant DNA Advisory Committee

    OpenAIRE

    Wivel, Nelson A.

    2014-01-01

    Science is host to a constantly emerging series of new paradigms, and it is this characteristic that makes science both interesting and dynamic. As a part of this continuum, it became possible to create recombinant DNA molecules. Immediately it was recognized that there was a potential for serious adverse events associated with this new technology. Following two scientific conferences at Asilomar, California, the National Institutes of Health moved quickly to create the Recombinant DNA Adviso...

  9. Recombinant human migration inhibitory factor has adjuvant activity.

    OpenAIRE

    Weiser, W Y; Pozzi, L M; Titus, R G; David, J R

    1992-01-01

    Recombinant human migration inhibitory factor (MIF), isolated through functional expression cloning in COS-1 cells, up-regulates expression of genes encoding HLA-DR and interleukin 1 beta (IL-1 beta) and elaboration of IL-1 beta by human monocyte-derived macrophages. Administration of soluble bovine serum albumin or human immunodeficiency virus 120-kDa glycoprotein (HIV gp120) to mice in the presence of recombinant MIF together with incomplete Freund's adjuvant induced a strong T-cell prolife...

  10. Charm production asymmetries from heavy-quark recombination

    OpenAIRE

    Mehen, Thomas

    2003-01-01

    Charm asymmetries in fixed-target hadroproduction experiments are sensitive to power corrections to the QCD factorization theorem for heavy quark production. A power correction called heavy-quark recombination has recently been proposed to explain these asymmetries. In heavy-quark recombination, a light quark or antiquark participates in a hard scattering which produces a charm-anticharm quark pair. The light quark or antiquark emerges from the scattering with small momentum in the rest frame...

  11. Experimental approaches to the measurement of dielectronic recombination

    International Nuclear Information System (INIS)

    In dielectronic recombination, the first step involves a continuum electron which excites a previously bound electron and, in so doing, loses just enough energy to be captured in a bound state (nl). This results in a doubly excited ion of a lower charge state which may either autoionize or emit a photon resulting in a stabilized recombination. The complete signature of the event is an ion of reduced charge and an emitted photon. Methods of measuring this event are discussed

  12. NOVEL PROCESSES AND PRODUCTS FOR RECOMBINANT PRODUCTION OF BIOPHARMACEUTICALS

    OpenAIRE

    Giuliani, Maria

    2009-01-01

    The monoclonal antibody market represents the fastest-growing segment within the biopharmaceutical industry (Evans and Das 2005). Indeed, recombinant antibodies and antibody fragments are widespread tools for research, diagnostics and therapy (Joosten et al., 2003). Large-scale production of recombinant antibodies and antibody fragments requires a suitable expression system which has to be cheap, accessible for genetic modifications, easily scaled up for greater demands and safe for use in co...

  13. Production of recombinant antibody fragments in Bacillus megaterium

    OpenAIRE

    Jahn Dieter; Schirrmann Thomas; Biedendieck Rebekka; Roth Andreas; Hust Michael; Jordan Eva; Dübel Stefan

    2007-01-01

    Abstract Background Recombinant antibodies are essential reagents for research, diagnostics and therapy. The well established production host Escherichia coli relies on the secretion into the periplasmic space for antibody synthesis. Due to the outer membrane of Gram-negative bacteria, only a fraction of this material reaches the medium. Recently, the Gram-positive bacterium Bacillus megaterium was shown to efficiently secrete recombinant proteins into the growth medium. Here we evaluated B. ...

  14. Recombinant mouse interferon-gamma regulation of antibody production.

    OpenAIRE

    Johnson, H M; Torres, B A

    1983-01-01

    Interferon-gamma produced in monkey cells by transfection with mouse interferon-gamma cDNA suppressed the mouse in vitro antibody response in a manner similar to that of natural mouse interferon-gamma. Significant suppression was obtained with as little as 1 U of interferon. Recombinant human interferon-gamma produced by cloning in a similar fashion was not suppressive. Both the suppressive and the antiviral activities of recombinant interferon-gamma were neutralized by antibodies to mouse na...

  15. Fine-scale recombination and adaptive radiation could be linked.

    Science.gov (United States)

    Bodilis, Josselin

    2013-09-15

    The difficult reconstruction of the evolutionary history of the major surface protein gene oprF highlighted an adaptive radiation in the Pseudomonas fluorescens group. The recent work of Hao (2013) showed that partial recombination events in oprF gene occurred specifically in a P. fluorescens lineage under ecological niche segregation. So, I suggest that identification of lineage-specific fine-scale recombination may be a way to detect putative adaptive radiation in bacteria. PMID:23774687

  16. Moment closure in a Moran model with recombination

    CERN Document Server

    Baake, Ellen

    2011-01-01

    We extend the Moran model with single-crossover recombination to include general recombination and mutation. We show that, in the case without resampling, the expectations of products of marginal processes defined via partitions of sites form a closed hierarchy, which is exhaustively described by a finite system of differential equations. One thus has the exceptional situation of moment closure in a nonlinear system. Surprisingly, this property is lost when resampling (i.e., genetic drift) is included.

  17. A Heritable Recombination System for Synthetic Darwinian Evolution in Yeast

    OpenAIRE

    Romanini, Dante W.; Peralta-Yahya, Pamela; Mondol, Vanessa; Cornish, Virginia W.

    2012-01-01

    Genetic recombination is central to the generation of molecular diversity and enhancement of evolutionary fitness in living systems. Methods such as DNA shuffling that recapitulate this diversity mechanism in vitro are powerful tools for engineering biomolecules with useful new functions by directed evolution. Synthetic biology now brings demand for analogous technologies that enable the controlled recombination of beneficial mutations in living cells. Thus, here we create a Heritable Recombi...

  18. Recombining binomial tree for constant elasticity of variance process

    OpenAIRE

    Hi Jun Choe; Jeong Ho Chu; So Jeong Shin

    2014-01-01

    The theme in this paper is the recombining binomial tree to price American put option when the underlying stock follows constant elasticity of variance(CEV) process. Recombining nodes of binomial tree are decided from finite difference scheme to emulate CEV process and the tree has a linear complexity. Also it is derived from the differential equation the asymptotic envelope of the boundary of tree. Conducting numerical experiments, we confirm the convergence and accuracy of the pricing by ou...

  19. Multiple biological activities of human recombinant interleukin 1.

    OpenAIRE

    Dinarello, C A; Cannon, J. G.; Mier, J W; Bernheim, H. A.; LoPreste, G; Lynn, D L; Love, R N; Webb, A C; Auron, P. E.; Reuben, R C

    1986-01-01

    Complementary DNA coding for human monocyte interleukin 1 (IL-1), pI 7 form, was expressed in Escherichia coli. During purification, IL-1 activity on murine T cells was associated with the recombinant protein. Homogeneous human recombinant IL-1 (hrIL-1) was tested in several assays to demonstrate the immunological and inflammatory properties attributed to this molecule. hrIL-1 induced proliferative responses in a cloned murine T cell in the presence of suboptimal concentrations of mitogen, wh...

  20. The next wave of recombinant and synthetic anticancer vaccines

    OpenAIRE

    Irvine, Kari R.; Restifo, Nicholas P

    1995-01-01

    The identification of tumor-associated antigens (TAA) recognized by T lymphocytes makes the development of antigen-specific synthetic and recombinant vaccines possible. The expression of TAA within a recombinant vector increases control over the kinetics and quantity, the molecular form, and the subcellular location of the immunogen delivered. The next generation of antitumor vaccines employs cytokines and costimulatory molecules expressed in concert with TAA that are capable of augmenting th...

  1. Genetic characterization of somatic recombination in Trichoderma pseudokoningii

    Directory of Open Access Journals (Sweden)

    Barcellos Fernando Gomes

    2003-01-01

    Full Text Available Crossing experiments via hyphal anastomosis between two strains contrasting for auxotrophic markers of Trichoderma pseudokoningii were conducted to characterize the somatic recombination process in this specie. Four crossings were made and a total of 1052 colonies obtained from conidial suspensions of the heterokaryotic colonies were analyzed. Sixty-eight recombinant colonies, from four growing generations, were analyzed for the auxotrophic markers. Of the 68 colonies analyzed, 58 were stable after four generations and the remainders were unstable, reverting to one of the parentals. Most of the recombinant colonies were unstable through subculture and after four growing generations they showed the leu ino met markers (auxotrophic for leucin, inositol and metionin respectively. The unstable recombinant colonies showed irregular growing borders, sparse sporulation and frequent sector formation. The results suggest the occurrence of recombination mechanisms in the heterokaryon (somatic recombination, different from those described for the parasexual cycle or parameiosis. Therefore, we proposed the ocurrence of nuclei degradation from one parental (non prevalent parental in the heterokaryon and that the resulting chromosomal fragments may be incorporated into whole nuclei of the another parental (prevalent parental. However the parameiosis as originally described cannot be excluded.

  2. Enhanced defects recombination in ion irradiated SiC

    Energy Technology Data Exchange (ETDEWEB)

    Izzo, G. [Department of Physics and Astronomy, Catania University, Via S. Sofia 64, 95123 Catania (Italy); Litrico, G., E-mail: grazia.litrico@ct.infn.i [Department of Physics and Astronomy, Catania University, Via S. Sofia 64, 95123 Catania (Italy); Grassia, F.; Calcagno, L.; Foti, G. [Department of Physics and Astronomy, Catania University, Via S. Sofia 64, 95123 Catania (Italy)

    2010-10-01

    Point defects induced in SiC by ion irradiation show a recombination at temperatures as low as 320 K and this process is enhanced after running current density ranging from 80 to 120 A/cm{sup 2}. Ion irradiation induces in SiC the formation of different defect levels and low-temperature annealing changes their concentration. Some levels (S{sub 0}, S{sub x} and S{sub 2}) show a recombination and simultaneously a new level (S{sub 1}) is formed. An enhanced recombination of defects is besides observed after running current in the diode at room temperature. The carriers introduction reduces the S{sub 2} trap concentration, while the remaining levels are not modified. The recombination is negligible up to a current density of 50 A/cm{sup 2} and increases at higher current density. The enhanced recombination of the S{sub 2} trap occurs at 300 K, which otherwise requires a 400 K annealing temperature. The process can be related to the electron-hole recombination at the associated defect.

  3. Homologous recombination in DNA repair and DNA damage tolerance

    Institute of Scientific and Technical Information of China (English)

    Xuan Li; Wolf-Dietrich Heyer

    2008-01-01

    Homologous recombination (HR) comprises a series of interrelated pathways that function in the repair of DNA double-stranded breaks (DSBs) and interstrand crosslinks (ICLs). In addition, recombination provides critical sup-port for DNA replication in the recovery of stalled or broken replication forks, contributing to tolerance of DNA damage. A central core of proteins, most critically the RecA homolog Rad51, catalyzes the key reactions that typify HR: homology search and DNA strand invasion. The diverse functions of recombination are reflected in the need for context-specific factors that perform supplemental functions in conjunction with the core proteins. The inability to properly repair complex DNA damage and resolve DNA replication stress leads to genomic instability and contributes to cancer etiology. Mutations in the BRCA2 recombination gene cause predisposition to breast and ovarian cancer as well as Fanconi anemia, a cancer predisposition syndrome characterized by a defect in the repair of DNA interstrand crosslinks. The cellular functions of recombination are also germane to DNA-based treatment modaUties of cancer, which target replicating cells by the direct or indirect induction of DNA lesions that are substrates for recombination pathways. This review focuses on mechanistic aspects of HR relating to DSB and ICL repair as well as replication fork support.

  4. Recombination and population inversion in plasmas generated by tunneling ionization.

    Science.gov (United States)

    Pert, G J

    2006-06-01

    Above-threshold ionization (ATI) ionization by linearly polarized light has been proposed by several authors as a means of driving recombination lasers in the soft x-ray spectral region. The pump radiation generates a cold electron plasma with ions in a single ionization stage, which is an ideal starting condition for strong recombination. Population inversions form during the recombination cascade to the ground state of the next ionization stage. In the absence of any relaxation the electron distribution is strongly peaked near zero energy. However, a number of different processes all heat the cold electrons towards Maxwellian, and may thereby reduce the recombination rate in the higher levels. Using numerical models we investigate these relaxation processes and their effect on recombination. We show that the recombination can be well described by the standard cascade model, provided an appropriate temperature is used. We examine two cases in detail, hydrogen-like lithium where the inversion is with respect to the ground state, and lithium-like nitrogen where it is with the first excited state. The two cases differ markedly in the degree of relaxation achieved, and in the duration of the population inversion.

  5. Meiotic recombination analysis in female ducks (Anas platyrhynchos).

    Science.gov (United States)

    Pigozzi, M I; Del Priore, L

    2016-06-01

    Meiotic recombination in female ducks was directly studied by immunolocalization of MLH1 protein, a mismatch repair protein of mature recombination nodules. In total, 6820 crossovers were scored along the autosomal synaptonemal complexes in 122 meiotic nuclei. From this analysis we predict that the female map length of the duck is 2845 cM, with a genome wide recombination rate of 2 cM/Mb. MLH1-focus mapping along the six largest bivalents shows regional variations of recombination frequencies that can be linked to differences in chromosome morphology. From this MLH1 mapping it can be inferred that distally located markers will appear more separated in genetic maps than physically equidistant markers located near the centromeres on bivalents 1 and 2. Instead, markers at interstitial positions on the acrocentric bivalents 3-6 will appear more tightly linked than expected on the basis of their physical distance because recombination is comparatively lower at the mid region of these chromosomes. The present results provide useful information to complement linkage mapping in ducks and extend previous knowledge about the variation of recombination rates among domestic Galloanserae.

  6. A novel and simple method for construction of recombinant adenoviruses.

    Science.gov (United States)

    Tan, Rong; Li, Chunhua; Jiang, Sijing; Ma, Lixin

    2006-07-19

    Recombinant adenoviruses have been widely used for various applications, including protein expression and gene therapy. We herein report a new and simple cloning approach to an efficient and robust construction of recombinant adenoviral genomes based on the mating-assisted genetically integrated cloning (MAGIC) strategy. The production of recombinant adenovirus serotype 5-based vectors was greatly facilitated by the use of the MAGIC procedure and the development of the Adeasy adenoviral vector system. The recombinant adenoviral plasmid can be generated by a direct and seamless substitution, which replaces the stuff fragment in a full-length adenoviral genome with the gene of interest in a small plasmid in Escherichia coli. Recombinant adenoviral plasmids can be rapidly constructed in vivo by using the new method, without manipulations of the large adenoviral genome. In contrast to other traditional systems, it reduces the need for multiple in vitro manipulations, such as endonuclease cleavage, ligation and transformation, thus achieving a higher efficiency with negligible background. This strategy has been proven to be suitable for constructing an adenoviral cDNA expression library. In summary, the new method is highly efficient, technically less demanding and less labor-intensive for constructing recombinant adenoviruses, which will be beneficial for functional genomic and proteomic researches in mammalian cells.

  7. Collision and recombination driven instabilities in variable charged dusty plasmas

    Indian Academy of Sciences (India)

    S Bal; M Bose

    2013-04-01

    The dust-acoustic instability driven by recombination of electrons and ions on the surface of charged and variably-charged dust grains as well as by collisions in dusty plasmas with significant pressure of background neutrals have been theoretically investigated. The recombination driven instability is shown to be dominant in the long wavelength regime even in the presence of dust-neutral and ion-neutral collisions, while in the shorter wavelength regime, the dust-neutral collision is found to play a major role. In an earlier research work, the dust-neutral collision was neglected in comparison to the effect due to the recombination for estimating the dust-acoustic instability; later the other report shows that the recombination effect is negligible in the presence of dust-neutral collisions. In line of this present situation our investigation revealed that the recombination is more important than dust-neutral collisions in laboratory plasma and fusion plasma, while the dust-neutral collision frequency is dominant in the interstellar plasmas. The effects of ion and dust densities and ion streaming on the recombination and collision driven mode in parameter regimes relevant for many experimental studies on dusty plasmas have also been calculated.

  8. Determination of the trap-assisted recombination strength in polymer light emitting diodes

    NARCIS (Netherlands)

    Kuik, M.; Nicolai, H.T.; Lenes, M.; Wetzelaer, G.-J.A.H.; Lu, M.; Blom, P.W.M.

    2011-01-01

    The recombination processes in poly(p -phenylene vinylene) based polymer light-emitting diodes (PLEDs) are investigated. Photogenerated current measurements on PLED device structures reveal that next to the known Langevin recombination also trap-assisted recombination is an important recombination c

  9. A universal BMV-based RNA recombination system--how to search for general rules in RNA recombination.

    Science.gov (United States)

    Alejska, Magdalena; Figlerowicz, Magdalena; Malinowska, Nelli; Urbanowicz, Anna; Figlerowicz, Marek

    2005-07-07

    At present, there is no doubt that RNA recombination is one of the major factors responsible for the generation of new RNA viruses and retroviruses. Numerous experimental systems have been created to investigate this complex phenomenon. Consequently, specific RNA structural motifs mediating recombination have been identified in several viruses. Unfortunately, up till now a unified model of genetic RNA recombination has not been formulated, mainly due to difficulties with the direct comparison of data obtained for different RNA-based viruses. To solve this problem, we have attempted to construct a universal system in which the recombination activity of various RNA sequences could be tested. To this end, we have used brome mosaic virus, a model (+)RNA virus of plants, for which the structural requirements of RNA recombination are well defined. The effectiveness of the new homomolecular system has been proven in an experiment involving two RNA sequences derived from the hepatitis C virus genome. In addition, comparison of the data obtained with the homomolecular system with those generated earlier using the heteromolecular one has provided new evidence that the mechanisms of homologous and non-homologous recombination are different and depend on the virus' mode of replication.

  10. Effects of the rad52 gene on recombination in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Effects of the rad52 mutation in Saccharomyces cerevisiae on meiotic, γ-ray-induced, uv-induced, and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Intra- and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the hisl-1/hisl-315 and trp5-2/trp5-48 heteroalleles. Gene-centromere recombination was also not observed in rad52/rad52 diploids. No γ-ray-induced intragenic mitotic recombination is seen in rad52/rad52 diploids and uv-induced intragenic recombination is greatly reduced. However, spontaneous mitotic recombination is not similarly affected. The RAD52 gene thus functions in recombination in meiosis and in γ-ray and uv-induced mitotic recombination but not in spontaneous mitotic recombination

  11. Recombination and assortment in the macronucleus of Tetrahymena thermophila: a theoretical study by computer simulation.

    Science.gov (United States)

    Doerder, F P; Diblasi, S L

    1984-12-01

    The compound nature of the macronucleus of Tetrahymena thermophila presents multiple opportunities for recombination between genes on the same macronuclear chromosome. Such recombinants should be detectable through their assortment at subsequent amitotic macronuclear divisions. Thus, a macronucleus that is initially AB/ab should produce recombinant assortees of the genotypes Ab/aB. Computer simulation shows that, when the recombination frequency is two or fewer times per cell cycle, recombinant assortees are produced at experimentally measurable frequencies of less than 40%. At higher recombination frequencies, linked genes appear to assort independently. The simulations also show that recombination during macronuclear development can be distinguished from recombination in subsequent cell cycles only if the first appearance of recombinant assortees is 100 or more fissions after conjugation. The use of macronuclear recombination and assortment as a means of mapping macronuclear genes is severely constrained by the large variances in assortment outcomes; with experimentally small sample sizes, such mapping is impossible.

  12. Transforming the treatment for hemophilia B patients: update on the clinical development of recombinant fusion protein linking recombinant coagulation factor IX with recombinant albumin (rIX-FP).

    Science.gov (United States)

    Santagostino, Elena

    2016-05-01

    Recombinant fusion protein linking recombinant coagulation factor IX with recombinant albumin (rIX-FP; Idelvion®(†)) is an innovative new treatment designed to extend the half-life of factor IX (FIX) and ease the burden of care for hemophilia B patients. The rIX-FP clinical development program - PROLONG-9FP - is in its advanced phases, with pivotal studies in previously treated adults, adolescents, and pediatrics now completed. Across all age groups studied, rIX-FP has demonstrated a markedly improved pharmacokinetic profile compared with plasma-derived and recombinant FIX treatments, with a 30-40% higher incremental recovery, an approximately 5-fold longer half-life, a lower clearance, and a greater area under the curve. rIX-FP has been very well tolerated with an excellent safety profile. In the pivotal studies, there have been no reports of FIX inhibitors or antidrug antibodies, and few treatment-related adverse events have been observed. Prophylactic regimens of rIX-FP administered once weekly to once every 14 days have been highly effective. When used for surgical prophylaxis, a single infusion of rIX-FP has been sufficient to maintain hemostasis, even during major orthopedic surgery. An ongoing study is now enrolling previously untreated patients and evaluating the possibility of extending the dosing interval to every 21 days. There is little doubt that rIX-FP will transform the treatment of hemophilia B. PMID:27288064

  13. Modelling of the operational behaviour of passive autocatalytic recombiners

    International Nuclear Information System (INIS)

    Due to severe accidents in nuclear power plants, a significant amount of hydrogen can be produced. In pressurized water reactors, a possible and wide-spread measurement is the use of auto-catalytic recombiners. There are numerous numerical models describing the operational behaviour of recombiners for containment codes. The numerical model REKO-DIREKT was developed at the Forschungszentrum Juelich. This model describes the chemical reaction on the catalytic sheets by a physical model, as opposed to the usual codes based on empirical correlations. Additionally, there have been experimental studies concerning the catalytic recombination of hydrogen since the 1990s. The aim of this work is the further development of the program REKO-DIREKT to an independent recombiner model for severe accident and containment codes. Therefore, the catalyst model already existed has been submitted by a parameter optimization with an experimental database expanded during this work. In addition, a chimney model has been implemented which allows the calculation of the free convection flow through the recombiner housing due to the exothermal reaction. This model has been tested by experimental data gained by a recently built test facility. The complete recombiner model REKO-DIREKT has been validated by data from literature. Another aim of this work is the derivation of the reaction kinetics for recombiner designs regarding future reactor concepts. Therefore, experimental studies both on single catalytic coated meshes as well as on two meshes installed in a row have been performed in laboratory scale. By means of the measured data, a theoretical approach for the determination of the reaction rate has been derived.

  14. Enhanced levels of λ Red-mediated recombinants in mismatch repair mutants

    OpenAIRE

    Costantino, Nina; Court, Donald L.

    2003-01-01

    Homologous recombination can be used to generate recombinants on episomes or directly on the Escherichia coli chromosome with PCR products or synthetic single-stranded DNA (ssDNA) oligonucleotides (oligos). Such recombination is possible because bacteriophage λ-encoded functions, called Red, efficiently recombine linear DNA with homologies as short as 20–70 bases. This technology, termed recombineering, provides ways to modify genes and segments of the chromosome as well as to study homologou...

  15. CRISPR-Cas9-assisted recombineering in Lactobacillus reuteri.

    Science.gov (United States)

    Oh, Jee-Hwan; van Pijkeren, Jan-Peter

    2014-01-01

    Clustered regularly interspaced palindromic repeats (CRISPRs) and the CRISPR-associated (Cas) nuclease protect bacteria and archeae from foreign DNA by site-specific cleavage of incoming DNA. Type-II CRISPR-Cas systems, such as the Streptococcus pyogenes CRISPR-Cas9 system, can be adapted such that Cas9 can be guided to a user-defined site in the chromosome to introduce double-stranded breaks. Here we have developed and optimized CRISPR-Cas9 function in the lactic acid bacterium Lactobacillus reuteri ATCC PTA 6475. We established proof-of-concept showing that CRISPR-Cas9 selection combined with single-stranded DNA (ssDNA) recombineering is a realistic approach to identify at high efficiencies edited cells in a lactic acid bacterium. We show for three independent targets that subtle changes in the bacterial genome can be recovered at efficiencies ranging from 90 to 100%. By combining CRISPR-Cas9 and recombineering, we successfully applied codon saturation mutagenesis in the L. reuteri chromosome. Also, CRISPR-Cas9 selection is critical to identify low-efficiency events such as oligonucleotide-mediated chromosome deletions. This also means that CRISPR-Cas9 selection will allow identification of recombinant cells in bacteria with low recombineering efficiencies, eliminating the need for ssDNA recombineering optimization procedures. We envision that CRISPR-Cas genome editing has the potential to change the landscape of genome editing in lactic acid bacteria, and other Gram-positive bacteria. PMID:25074379

  16. In vivo metabolism of recombinant human erythropoietin in the rat

    Energy Technology Data Exchange (ETDEWEB)

    Spivak, J.L.; Hogans, B.B.

    1989-01-01

    We compared the in vivo plasma clearance and organ accumulation in anesthetized rats of 125I-labeled, recombinant human erythropoietin and 125I-labeled, desialylated recombinant erythropoietin. The immediate volume of distribution of 125I-labeled, recombinant erythropoietin approximated that of the plasma volume. Its plasma clearance was multiexponential, with an initial rapid distribution phase (t1/2 = 53 minutes) and a slower elimination phase (t1/2 = 180 minutes). Organ accumulation of labeled recombinant erythropoietin, as compared with 125I-labeled human albumin, was negligible until 30 minutes after injection when small amounts appeared in the kidneys and bone marrow. Only 24% of the 125I-labeled, desialylated recombinant erythropoietin was recovered immediately after injection, and 96% of the hormone was cleared from the plasma with a t1/2 of 2.0 minutes. The bulk of the desialylated hormone accumulated in the liver where it was rapidly catabolized and its breakdown products released back into the plasma. Significantly, in contrast to unmodified erythropoietin, there was also early accumulation of desialylated hormone in the kidneys, marrow, and spleen. Desialylated orosomucoid but not orosomucoid, yeast mannan, or dextran sulfate 500 inhibited the rapid plasma clearance and hepatic accumulation of desialylated erythropoietin. Oxidation of the desialylated hormone restored its plasma recovery and clearance to normal but rendered it biologically inactive, and accumulation in organs other than the kidney was negligible.

  17. The recombination landscape in Arabidopsis thaliana F2 populations.

    Science.gov (United States)

    Salomé, P A; Bomblies, K; Fitz, J; Laitinen, R A E; Warthmann, N; Yant, L; Weigel, D

    2012-04-01

    Recombination during meiosis shapes the complement of alleles segregating in the progeny of hybrids, and has important consequences for phenotypic variation. We examined allele frequencies, as well as crossover (XO) locations and frequencies in over 7000 plants from 17 F(2) populations derived from crosses between 18 Arabidopsis thaliana accessions. We observed segregation distortion between parental alleles in over half of our populations. The potential causes of distortion include variation in seed dormancy and lethal epistatic interactions. Such a high occurrence of distortion was only detected here because of the large sample size of each population and the number of populations characterized. Most plants carry only one or two XOs per chromosome pair, and therefore inherit very large, non-recombined genomic fragments from each parent. Recombination frequencies vary between populations but consistently increase adjacent to the centromeres. Importantly, recombination rates do not correlate with whole-genome sequence differences between parental accessions, suggesting that sequence diversity within A. thaliana does not normally reach levels that are high enough to exert a major influence on the formation of XOs. A global knowledge of the patterns of recombination in F(2) populations is crucial to better understand the segregation of phenotypic traits in hybrids, in the laboratory or in the wild. PMID:22072068

  18. Suppression of auger recombination in ""giant"" core/shell nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Santamaria, Florencio [Los Alamos National Laboratory; Vela, Javier [Los Alamos National Laboratory; Schaller, Richard D [Los Alamos National Laboratory; Hollingsworth, Jennifer A [Los Alamos National Laboratory; Klimov, Victor I [Los Alamos National Laboratory; Chen, Yongfen [NON LANL

    2009-01-01

    Many potential applications of semiconductor nanocrystals are hindered by nonradiative Auger recombination wherein the electron-hole (exciton) recombination energy is transferred to a third charge carrier. This process severely limits the lifetime and bandwidth of optical gain, leads to large nonradiative losses in light emitting diodes and photovoltaic cells, and is believed to be responsible for intermittency ('blinking') of emission from single nanocrystals. The development of nanostructures in which Auger recombination is suppressed has been a longstanding goal in colloidal nanocrystal research. Here, we demonstrate that such suppression is possible using so-called 'giant' nanocrystals that consist of a small CdSe core and a thick CdS shell. These nanostructures exhibit a very long biexciton lifetime ({approx}10 ns) that is likely dominated by radiative decay instead of non-radiative Auger recombination. As a result of suppressed Auger recombination, even high-order multiexcitons exhibit high emission efficiencies, which allows us to demonstrate optical amplification with an extraordinarily large bandwidth (>500 me V) and record low excitation thresholds.

  19. Recombination spot identification Based on gapped k-mers.

    Science.gov (United States)

    Wang, Rong; Xu, Yong; Liu, Bin

    2016-01-01

    Recombination is crucial for biological evolution, which provides many new combinations of genetic diversity. Accurate identification of recombination spots is useful for DNA function study. To improve the prediction accuracy, researchers have proposed several computational methods for recombination spot identification. The k-mer feature is one of the most useful features for modeling the properties and function of DNA sequences. However, it suffers from the inherent limitation. If the value of word length k is large, the occurrences of k-mers are closed to a binary variable, with a few k-mers present once and most k-mers are absent. This usually causes the sparse problem and reduces the classification accuracy. To solve this problem, we add gaps into k-mer and introduce a new feature called gapped k-mer (GKM) for identification of recombination spots. By using this feature, we present a new predictor called SVM-GKM, which combines the gapped k-mers and Support Vector Machine (SVM) for recombination spot identification. Experimental results on a widely used benchmark dataset show that SVM-GKM outperforms other highly related predictors. Therefore, SVM-GKM would be a powerful predictor for computational genomics. PMID:27030570

  20. Recombinant host cells and media for ethanol production

    Science.gov (United States)

    Wood, Brent E; Ingram, Lonnie O; Yomano, Lorraine P; York, Sean W

    2014-02-18

    Disclosed are recombinant host cells suitable for degrading an oligosaccharide that have been optimized for growth and production of high yields of ethanol, and methods of making and using these cells. The invention further provides minimal media comprising urea-like compounds for economical production of ethanol by recombinant microorganisms. Recombinant host cells in accordance with the invention are modified by gene mutation to eliminate genes responsible for the production of unwanted products other than ethanol, thereby increasing the yield of ethanol produced from the oligosaccharides, relative to unmutated parent strains. The new and improved strains of recombinant bacteria are capable of superior ethanol productivity and yield when grown under conditions suitable for fermentation in minimal growth media containing inexpensive reagents. Systems optimized for ethanol production combine a selected optimized minimal medium with a recombinant host cell optimized for use in the selected medium. Preferred systems are suitable for efficient ethanol production by simultaneous saccharification and fermentation (SSF) using lignocellulose as an oligosaccharide source. The invention also provides novel isolated polynucleotide sequences, polypeptide sequences, vectors and antibodies.

  1. Novel Heterotypic Rox Sites for Combinatorial Dre Recombination Strategies

    Directory of Open Access Journals (Sweden)

    Katherine Chuang

    2016-03-01

    Full Text Available Site-specific recombinases (SSRs such as Cre are widely used in gene targeting and genetic approaches for cell labeling and manipulation. They mediate DNA strand exchange between two DNA molecules at dedicated recognition sites. Precise understanding of the Cre recombination mechanism, including the role of individual base pairs in its loxP target site, guided the generation of mutant lox sites that specifically recombine with themselves but not with the wild type loxP. This has led to the development of a variety of combinatorial Cre-dependent genetic strategies, such as multicolor reporters, irreversible inversions, or recombination-mediated cassette exchange. Dre, a Cre-related phage integrase that recognizes roxP sites, does not cross-react with the Cre-loxP system, but has similar recombination efficiency. We have previously described intersectional genetic strategies combining Dre and Cre. We now report a mutagenesis screen aimed at identifying roxP base pairs critical for self-recognition. We describe several rox variant sites that are incompatible with roxP, but are able to efficiently recombine with themselves in either purified systems or bacterial and eukaryotic tissue culture systems. These newly identified rox sites are not recognized by Cre, thus enabling potential combinatorial strategies involving Cre, Dre, and target loci including multiple loxP and roxP variants.

  2. Temporally-controlled site-specific recombination in zebrafish.

    Directory of Open Access Journals (Sweden)

    Stefan Hans

    Full Text Available Conventional use of the site-specific recombinase Cre is a powerful technology in mouse, but almost absent in other vertebrate model organisms. In zebrafish, Cre-mediated recombination efficiency was previously very low. Here we show that using transposon-mediated transgenesis, Cre is in fact highly efficient in this organism. Furthermore, temporal control of recombination can be achieved by using the ligand-inducible CreER(T2. Site-specific recombination only occurs upon administration of the drug tamoxifen (TAM or its active metabolite, 4-hydroxy-tamoxifen (4-OHT. Cre-mediated recombination is detectable already 4 or 2 hours after administration of TAM or 4-OHT, demonstrating fast recombination kinetics. In addition, low doses of TAM allow mosaic labeling of single cells. Combined, our results show that conditional Cre/lox will be a valuable tool for both, embryonic and adult zebrafish studies. Furthermore, single copy insertion transgenesis of Cre/lox constructs suggest a strategy suitable also for other organisms.

  3. Expression of recombination-activating genes and T cell receptor gene recombination in the human T cell leukemia cell line

    Institute of Scientific and Technical Information of China (English)

    ZOU Hong-yun; MA Li; MENG Min-jie; YAO Xin-sheng; LIN Ying; WU Zhen-qiang; HE Xiao-wei; WANG Ju-fang; WANG Xiao-ning

    2007-01-01

    Background Recent studies have suggested that mature T cells can change their specificity through reexpression of recombination-activating genes (RAG) and RAG-mediated V(D)J recombination. This process is named receptor revision and has been observed in mature peripheral T cells from transgenic mice and human donors. However, whether the receptor revision in mature T cells is a random or orientated process remains poorly understood. Here we used the Jurkat human T cell line, which represents a mature stage of T cell development, as a model to investigate the regulation of T cell receptor (TCR) gene recombination.Methods TCR Dβ-Jβ signal joint T cell receptor excision DNA circles (sjTRECs) were determined by nested and seminested PCR. Double-strand DNA breaks at recombination signal sequences (RSSs) in the TCRVβ chain locus were detected by ligation-mediated-PCR. Further analysis of the complementarity-determining region 3 (CDR3) size of the TCRVβ chain was examined by the TCR GeneScan technique.Results RAG1, RAG2, and three crucial components of the nonhomologous DNA end-joining (NHEJ) pathway were readily detected in Jurkat. Characteristics of junctional diversity of Dβ2-Jβ2 signal joints and ds RSS breaks associated with the Dβ25' and Dβ 23' sites were detected in DNA from Jurkat cells. CDR3 size and the gene sequences of the TCRVβ chain did not change during cell proliferation.Conclusions RAG1 and RAG2 and ongoing TCR gene recombination are coexpressed in Jurkat cells, but the ongoing recombination process may not play a role in modification of the TCR repertoire. However, the results suggest that Jurkat could be used as a model for studying the regulation of RAGs and V(D)J recombination and as a "special" model of the coexistence of TCR gene rearrangements and "negative" receptor revision.

  4. Radiative instabilities in plasmas: impurity motion and recombination effects

    International Nuclear Information System (INIS)

    Radiative instabilities in an impurity-seeded plasma are investigated when the plasma is supposed to be highly but partially ionized. Since in such plasmas radiative losses strongly depend on neutral and impurity densities, their dynamics are taken into account. As a result, a new radiative-recombination instability is found and described. We show that the influence of the ionization-recombination balance on plasma stability is sufficient for plasma densities above 1014 cm-3. The effects of a finite impurity Larmor radius are not small and play a stabilizing role as well as the thermal forces. On the other hand, compressibility of the magnetic field leads to plasma destabilization. We note that this radiative-recombination instability accumulates impurities in a cold zone while cleaning other regions. (Author)

  5. Taxing the Rich: Recombinations and Bubble Growth During Reionization

    CERN Document Server

    Furlanetto, S R; Furlanetto, Steven R.

    2005-01-01

    Reionization is inhomogeneous for two reasons: the clumpiness of the intergalactic medium (IGM) and clustering of the discrete ionizing sources. While numerical simulations can in principle take both into account, they are at present limited by small box sizes. On the other hand, analytic models have only examined the limiting cases of a clumpy IGM (with uniform ionizing emissivity) and clustered sources (embedded in a uniform IGM). Here, we present an analytic model for the evolving topology of reionization that includes both factors. At first, recombinations can be ignored and ionized bubbles grow primarily through major mergers. As a result, reionization resembles "punctuated equilibrium," with a series of well-separated sharp jumps in the ionizing background. These features are local effects and do not reflect similar jumps in the global ionized fraction. We then combine our bubble model with a simple description of recombinations in the IGM. We show that the bubbles stop growing when recombinations balan...

  6. Evidence for recombination in Crimean-Congo hemorrhagic fever virus.

    Science.gov (United States)

    Lukashev, Alexander N

    2005-08-01

    Crimean-Congo hemorrhagic fever (CCHF) virus has attracted considerable attention recently and a number of phylogenetic studies have been published, based mostly on partial sequences of S and M RNA segments. In this study, available full-length S, M and L segment sequences of CCHF virus were checked for recombination. Similarity plots and bootscan analysis of the S segment suggested multiple recombination events between southern European, Asian and African CCHF virus strains, with additional evidence provided by phylogenetic trees, the hidden Markov model and probabilistic divergence measures methods. No unambiguous signs of recombination were observed for M and L segments; however, the results did not exclude the possibility of this. These findings, coupled with a recent report on reassortment in CCHF virus, suggest caution when assessing CCHF virus phylogeny based on short sequence fragments.

  7. Radiative and interfacial recombination in CdTe heterostructures

    International Nuclear Information System (INIS)

    Double heterostructures (DH) were produced consisting of a CdTe film between two wide band gap barriers of CdMgTe alloy. A combined method was developed to quantify radiative and non-radiative recombination rates by examining the dependence of photoluminescence (PL) on both excitation intensity and time. The measured PL characteristics, and the interface state density extracted by modeling, indicate that the radiative efficiency of CdMgTe/CdTe DHs is comparable to that of AlGaAs/GaAs DHs, with interface state densities in the low 1010 cm−2 and carrier lifetimes as long as 240 ns. The radiative recombination coefficient of CdTe is found to be near 10−10 cm3s−1. CdTe film growth on bulk CdTe substrates resulted in a homoepitaxial interface layer with a high non-radiative recombination rate

  8. Dielectronic Recombination of Sn10+ Ions and Related Satellite Spectra

    Institute of Scientific and Technical Information of China (English)

    FU Yan-Biao; DONG Chen-Zhong; SU Mao-Gen; Gerry O' Sullivan

    2008-01-01

    @@ Based on the multi-configuration Dirac-Fock method,theoretical calculations are carried out for the dielectronic recombination (DR) rate coefficients and the collision excitation rate coefficients of Sn10+ ions.It is found that the total DR rate coefficient has its maximum value between 10eV and 100eV and is greater than either the radiative recombination or three-body recombination rate coefficients (the number of free electrons per unit is 1021 cm3)for the case of Te >1 eV.Therefore,DR can strongly influence the ionization balance of laser produced multi-charged tin ions.The related dielectronic satellite cannot be ignored at low temperature Te<5 eV.

  9. An Overview of the Molecular Mechanisms of Recombinational DNA Repair.

    Science.gov (United States)

    Kowalczykowski, Stephen C

    2015-11-01

    Recombinational DNA repair is a universal aspect of DNA metabolism and is essential for genomic integrity. It is a template-directed process that uses a second chromosomal copy (sister, daughter, or homolog) to ensure proper repair of broken chromosomes. The key steps of recombination are conserved from phage through human, and an overview of those steps is provided in this review. The first step is resection by helicases and nucleases to produce single-stranded DNA (ssDNA) that defines the homologous locus. The ssDNA is a scaffold for assembly of the RecA/RAD51 filament, which promotes the homology search. On finding homology, the nucleoprotein filament catalyzes exchange of DNA strands to form a joint molecule. Recombination is controlled by regulating the fate of both RecA/RAD51 filaments and DNA pairing intermediates. Finally, intermediates that mature into Holliday structures are disjoined by either nucleolytic resolution or topological dissolution. PMID:26525148

  10. The dissociative recombination of fluorocarbon ions: II. CF{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Novotny, O [PALMS, UMR No 6627 du CNRS, Universite de Rennes I, 35042 Rennes (France); Mitchell, J B A [PALMS, UMR No 6627 du CNRS, Universite de Rennes I, 35042 Rennes (France); LeGarrec, J L [PALMS, UMR No 6627 du CNRS, Universite de Rennes I, 35042 Rennes (France); Florescu-Mitchell, A I [PALMS, UMR No 6627 du CNRS, Universite de Rennes I, 35042 Rennes (France); Rebrion-Rowe, C [PALMS, UMR No 6627 du CNRS, Universite de Rennes I, 35042 Rennes (France); Svendsen, A [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); El Ghazaly, M A [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Andersen, L H [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Ehlerding, A [Department of Physics, Stockholm University, Alba Nova, SE-106 91, Stockholm (Sweden); Viggiano, A A [Air Force Research Laboratory, Space Vehicles Directorate, 29 Randolph Road, Hanscom AFB, MA 01731 (United States); Hellberg, F [Department of Physics, Stockholm University, Alba Nova, SE-106 91, Stockholm (Sweden); Thomas, R D [Department of Physics, Stockholm University, Alba Nova, SE-106 91, Stockholm (Sweden); Zhaunerchyk, V [Department of Physics, Stockholm University, Alba Nova, SE-106 91, Stockholm (Sweden); Geppert, W D [Department of Physics, Stockholm University, Alba Nova, SE-106 91, Stockholm (Sweden); Montaigne, H [Department of Physics, Stockholm University, Alba Nova, SE-106 91, Stockholm (Sweden); Kaminska, M [Swietokrzyska Academy, 25-406 Kielce (Poland); Oesterdahl, F [Department of Physics, Royal Institute of Technology, Alba Nova, SE-106 91, Stockholm (Sweden); Larsson, M [Department of Physics, Stockholm University, Alba Nova, SE-106 91, Stockholm (Sweden)

    2005-05-28

    The dissociative recombination and excitation of CF{sup +} have been measured at the ASTRID and CRYRING storage rings. Though examination of the available potential energy curves would suggest that the recombination rate would be large for this ion, in fact a rate constant of 5.2 {+-} 1.0 x 10{sup -8} (T{sub e}/300){sup -0.8} cm{sup 3} s{sup -1} was found. The recombination cross section at low energies falls off to a minimum at 0.5 eV centre-of-mass collision energy but exhibits resonances at energies above this. The dissociative excitation cross section leading to C{sup +} + F was also measured and this displays an onset beginning at about 7 eV.

  11. Mechanisms underlying allergy vaccination with recombinant hypoallergenic allergen derivatives.

    Science.gov (United States)

    Linhart, Birgit; Valenta, Rudolf

    2012-06-19

    Hundred years ago therapeutic vaccination with allergen-containing extracts has been introduced as a clinically effective, disease-modifying, allergen-specific and long-lasting form of therapy for allergy, a hypersensitivity disease affecting more than 25% of the population. Today, the structures of most of the disease-causing allergens have been elucidated and recombinant hypoallergenic allergen derivatives with reduced allergenic activity have been engineered to reduce side effects during allergen-specific immunotherapy (SIT). These recombinant hypoallergens have been characterized in vitro, in experimental animal models and in clinical trials in allergic patients. This review provides a summary of the molecular, immunological and preclinical evaluation criteria applied for this new generation of allergy vaccines. Furthermore, we summarize the mechanisms underlying SIT with recombinant hypoallergens which are thought to be responsible for their therapeutic effect.

  12. Recombination Lines of CII in the Spectra of Planetary Nebulae

    CERN Document Server

    Sochi, Taha

    2010-01-01

    The current report presents the work carried out by the author to investigate the recombination lines of CII in the spectra of planetary nebulae. Two CIII targets were prepared and used to generate theoretical data required in the investigation of recombination lines that arise from collisions between electrons and ions in thin plasma found in planetary nebulae and other astrophysical objects. One of these targets contains 9 atomic terms while the other contains 26 terms. For each one of these targets, theoretical data concerning bound and autoionizing states were generated in the intermediate coupling approximation by R-matrix and Autostructure codes and compared to experimental data. The comparison revealed very good agreement. These theoretical data were then used to generate emissivity data and compare it to the carbon recombination lines found in the observational line list of Zhang et al [2005] on the planetary nebula NGC 7027. The main tool used in this analysis is the `Emissivity' code which is a prog...

  13. Charge recombination in CuPc/PTCDA thin films.

    Science.gov (United States)

    Heutz, S; Nogueira, A F; Durrant, J R; Jones, T S

    2005-06-16

    The recombination kinetics of photogenerated charge carriers in perylene-3, 4, 9, 10-tetracarboxylic dianhydride (PTCDA) and copper phthalocyanine (CuPc) thin films grown by organic molecular beam deposition have been studied using transient absorption spectroscopy. Optical excitation is observed to generate long-lived polaron states, which exhibit power law recombination dynamics on time scales from microseconds to milliseconds. Studies as a function of excitation density and temperature, and comparison between heterostructures and PTCDA single layers, all indicate that this power law behavior results from trapping of PTCDA- polarons in localized states, with an estimated trap state density of approximately 6 x 10(17) polarons cm(-3). This recombination behavior is found to be remarkably similar to that previously observed for polymer/fullerene blends, suggesting that it may be generic to a range of semiconducting materials.

  14. Recombination and collisional X-UV lasers at ORSAY

    Energy Technology Data Exchange (ETDEWEB)

    Klisnick, A.; Carillon, A.; Dhez, P.; Goedtkindt, P.; Guennou, H.; Jamelot, G.; Jaegle, P.; Sureau, A.; Rus, B.; Zeitoun, P. (Laboratoire de Spectroscopie Atomique et Ionique, Universite Paris-Sud, Bat. 350, 91405 Orsay Cedex (France)); Chenais-Popovics, C.; Renaudin, P.; Rancu, O.; Gauthier, J.C. (LULI: CNRS National Facility, Laboratoire pour l' Utilisation des Lasers Intenses, Ecole Polytechnique, 91128 Palaiseau Cedex (France)); Back, C.A. (Lawrence Livermore National Laboratory, Livermore, California 94550 (United States))

    1995-01-10

    In this paper we describe the progress achieved recently in our laboratory in the field of X-ray lasers. Both collisional excitation and recombination pumped systems are under investigation. We show that the 5g-4f transition in lithium-like ions could bring out a significant increase of the gain-length accessible with recombination X-ray lasers. We present preliminary results on an absorption spectroscopy experiment designed to probe the ionization state of recombination X-ray laser plasmas. Finally we report on the observation of a strong amplified signal at 212 A, the wavelength of a 3p-3s (J=0--1) in neon-like zinc. [copyright] 1995 [ital American] [ital Institute] [ital of] [ital Physics

  15. Thermalisation and recombination of subexcitation electrons in solid water

    Energy Technology Data Exchange (ETDEWEB)

    Goulet, T.; Jay-Gerin, J.-P. (Sherbrooke Univ., PQ (Canada). Faculte de Medicine); Patau, J.-P. (Toulouse-3 Univ., 31 (France))

    1990-01-01

    The results of Monte Carlo simulations of the thermalisation of subexcitation electrons in solid water are reported. In the simulations, the possibility is taken into account that, prior to being thermalised, the electrons either recombine with their parent cation (H{sub 2}O{sup +}), or undergo a dissociative attachment to water molecules. A particular emphasis is placed on the description of the recombination process and on the influence of the parent cation on the electron's motion. The simulations are performed for different initial electron energies E{sub o} in the subexcitations energy range (i.e. E{sub o} < 7.4 eV). For each of these energies, the mean thermalisation distance {sub th} and time {sub th} are determined, as well as the proportions P{sub rec} and P{sub dis} of subexcitation electrons which, instead of thermalising, undergo recombination or dissociative attachment. (author).

  16. Matter-wave recombiners for trapped Bose-Einstein condensates

    Science.gov (United States)

    Berrada, T.; van Frank, S.; Bücker, R.; Schumm, T.; Schaff, J.-F.; Schmiedmayer, J.; Julía-Díaz, B.; Polls, A.

    2016-06-01

    Interferometry with trapped atomic Bose-Einstein condensates (BECs) requires the development of techniques to recombine the two paths of the interferometer and map the accumulated phase difference to a measurable atom number difference. We have implemented and compared two recombining procedures in a double-well-based BEC interferometer. The first procedure utilizes the bosonic Josephson effect and controlled tunneling of atoms through the potential barrier, similar to laser light in an optical fiber coupler. The second one relies on the interference of the reflected and transmitted parts of the BEC wave function when impinging on the potential barrier, analogous to light impinging on a half-silvered mirror. Both schemes were implemented successfully, yielding an interferometric contrast of ˜20 % and 42% respectively. Building efficient matter-wave recombiners represents an important step towards the coherent manipulation of external quantum superposition states of BECs.

  17. Radio recombination lines from obscured quasars with the SKA

    Science.gov (United States)

    Manti, S.; Gallerani, S.; Ferrara, A.; Feruglio, C.; Graziani, L.; Bernardi, G.

    2016-02-01

    We explore the possibility of detecting hydrogen radio recombination lines from 0 recombination line flux observed at ν ˜ 1 GHz if recombinations arise in H II regions with Te ≈ 103 - 5 K, ne ≈ 103 - 5 cm-3. We compute the sensitivity required for a 5σ detection of Hnα lines using the Square Kilometre Array (SKA), finding that the SKA-MID could detect sources with MAB ≲ -27 (MAB ≲ -26) at z ≲ 8 (z ≲ 3) in less than 100 h of observing time. These observations could open new paths to searches for obscured SMBH progenitors, complementing X-ray, optical/IR and sub-mm surveys.

  18. Oligonucleotide recombination in corynebacteria without the expression of exogenous recombinases.

    Science.gov (United States)

    Krylov, Alexander A; Kolontaevsky, Egor E; Mashko, Sergey V

    2014-10-01

    Brevibacterium lactofermentum and Corynebacterium glutamicum are important biotechnology species of the genus Corynebacterium. The single-strand DNA annealing protein (SSAP)-independent oligonucleotide-mediated recombination procedure was successfully applied to the commonly used wild-type strains B. lactofermentum AJ1511 and C. glutamicum ATCC13032. When the rpsL gene was used as a target, the optimized protocol yielded up to (1.4±0.3)×10(3) and (6.7±1.3)×10(3) streptomycin-resistant colonies per 10(8) viable cells for the corresponding strains. We tested the influence of several parameters that are known to enhance the efficiency of oligonucleotide-mediated recombination in other bacterial species. Among them, increasing the concentration of oligonucleotides and targeting the lagging strand of the chromosome have proven to have positive effects on both of the tested species. No difference in the efficiency of recombination was observed between the oligonucleotides phosphorothiorated at the 5' ends and the unmodified oligonucleotides or between the oligonucleotides with four mutated nucleotides and those with one mutated nucleotide. The described approach demonstrates that during the adaptation of the recombineering technique, testing SSAP-independent oligonucleotide-mediated recombination could be a good starting point. Such testing could decrease the probability of an incorrect interpretation of the effect of exogenous protein factors (such as SSAP and/or corresponding exonucleases) due to non-optimal experimental conditions. In addition, SSAP-independent recombination itself could be useful in combination with suitable selection/enrichment methods. PMID:25087479

  19. Recombinant production of mecasermin in E. coli expression system.

    Science.gov (United States)

    Jafari, S; Babaeipour, V; Seyedi, H A Eslampanah; Rahaie, M; Mofid, M R; Haddad, L; Namvaran, M M; Fallah, J

    2014-01-01

    Human Insulin-like growth factor 1 (hIGF-1) consists of 70 amino acids in a single chain with three intermolecular disulfide bridges possessing valuable therapeutic effects. To date, numerous variants of specifically engineered hIGF-1 have been produced so as to improve hIGF-1 biological activity, stability and stronger binding to IGF-1 receptor. Mecasermin is one of the modified variants with one amino acid substitution near the N-terminal (T4I) approved for the treatment of growth failure diabetes, wound healing, amyotrophic lateral sclerosis and severe primary IGF-1 deficiency. No scientific report for recombinant production of mecasermin in Escherichia coli (E. coli) expression system has been sofar reported. In the present study, we therefore investigated the overexpression of mecasermin in two different E. coli strains in order to obtain higher yield of recombinant protein. To achieve this goal, mecasermin DNA encoding sequence was designed based on polypeptide sequence, optimized according to E. coli codon preference, and cloned in pET15b. Recombinant vector, pET15-mecasermin, transferred into two E. coli strains rigami B (DE3) and BL21 (DE3) and induced for expression in a small scale. Results revealed the E. coli Origami B (DE3) expression system was a preferable host for mecasermin production due to its high expression level being around twice as much as BL21 (DE3). Large scale mecasermin production was performed in batch culture and produced recombinant protein specifically confirmed by western blotting and mass spectroscopy. Since major part of recombinant mecasermin was expressed as inclusion body, isolation and refolding was accomplished through developed purification procedure, and finally recombinant protein was successfully purified by gel filtration chromatography. PMID:26339260

  20. Short telomeres initiate telomere recombination in primary and tumor cells.

    Directory of Open Access Journals (Sweden)

    Tammy A Morrish

    2009-01-01

    Full Text Available Human tumors that lack telomerase maintain telomeres by alternative lengthening mechanisms. Tumors can also form in telomerase-deficient mice; however, the genetic mechanism responsible for tumor growth without telomerase is unknown. In yeast, several different recombination pathways maintain telomeres in the absence of telomerase-some result in telomere maintenance with minimal effects on telomere length. To examine non-telomerase mechanisms for telomere maintenance in mammalian cells, we used primary cells and lymphomas from telomerase-deficient mice (mTR-/- and Emumyc+mTR-/- and CAST/EiJ mouse embryonic fibroblast cells. These cells were analyzed using pq-ratio analysis, telomere length distribution outliers, CO-FISH, Q-FISH, and multicolor FISH to detect subtelomeric recombination. Telomere length was maintained during long-term growth in vivo and in vitro. Long telomeres, characteristic of human ALT cells, were not observed in either late passage or mTR-/- tumor cells; instead, we observed only minimal changes in telomere length. Telomere length variation and subtelomeric recombination were frequent in cells with short telomeres, indicating that length maintenance is due to telomeric recombination. We also detected telomere length changes in primary mTR-/- cells that had short telomeres. Using mouse mTR+/- and human hTERT+/- primary cells with short telomeres, we found frequent length changes indicative of recombination. We conclude that telomere maintenance by non-telomerase mechanisms, including recombination, occurs in primary cells and is initiated by short telomeres, even in the presence of telomerase. Most intriguing, our data indicate that some non-telomerase telomere maintenance mechanisms occur without a significant increase in telomere length.

  1. Recombination accelerates adaptation on a large-scale empirical fitness landscape in HIV-1.

    Science.gov (United States)

    Moradigaravand, Danesh; Kouyos, Roger; Hinkley, Trevor; Haddad, Mojgan; Petropoulos, Christos J; Engelstädter, Jan; Bonhoeffer, Sebastian

    2014-06-01

    Recombination has the potential to facilitate adaptation. In spite of the substantial body of theory on the impact of recombination on the evolutionary dynamics of adapting populations, empirical evidence to test these theories is still scarce. We examined the effect of recombination on adaptation on a large-scale empirical fitness landscape in HIV-1 based on in vitro fitness measurements. Our results indicate that recombination substantially increases the rate of adaptation under a wide range of parameter values for population size, mutation rate and recombination rate. The accelerating effect of recombination is stronger for intermediate mutation rates but increases in a monotonic way with the recombination rates and population sizes that we examined. We also found that both fitness effects of individual mutations and epistatic fitness interactions cause recombination to accelerate adaptation. The estimated epistasis in the adapting populations is significantly negative. Our results highlight the importance of recombination in the evolution of HIV-I.

  2. Productive homologous and non-homologous recombination of hepatitis C virus in cell culture

    DEFF Research Database (Denmark)

    Scheel, Troels K H; Galli, Andrea; Li, Yi-Ping;

    2013-01-01

    . In addition, recombination is an important regulatory mechanism of cytopathogenicity for the related pestiviruses. Here we describe recombination of HCV RNA in cell culture leading to production of infectious virus. Initially, hepatoma cells were co-transfected with a replicating JFH1ΔE1E2 genome (genotype 2a...... incompetent genomes were co-transfected. Reverse genetic studies verified the viability of representative recombinants. After serial passage, subsequent recombination events reducing or eliminating the duplicated region were observed for some but not all recombinants. Furthermore, we found that inter......-genotypic recombination could occur, but at a lower frequency than intra-genotypic recombination. Productive recombination of attenuated HCV genomes depended on expression of all HCV proteins and tolerated duplicated sequence. In general, no strong site specificity was observed. Non-homologous recombination was observed...

  3. Influence of manganese ions on recombination luminescence in potassium phospate

    International Nuclear Information System (INIS)

    The investigation of recombination luminescence was carried out for crystal KDP doped by manganese ions after full and partial dehydration. It was established that manganese ions bring about increase the velocities of radiation defects accumulation in matrix. It was expected the appearance of two new TL peaks are connected with influence radiation defects thermal stability in matrix by impurity ions. The TL peal 100 K is connected with defect PO32-. The manganese ions become ion replacement after full dehydration. The radiation induced impurity defects are a centers of recombination. (author)

  4. Ovarian response to recombinant human follicle-stimulating hormone

    DEFF Research Database (Denmark)

    Arce, Joan-Carles; Andersen, Anders Nyboe; Fernández-Sánchez, Manuel;

    2014-01-01

    OBJECTIVE: To evaluate the dose-response relationship of a novel recombinant human FSH (rhFSH; FE 999049) with respect to ovarian response in patients undergoing IVF/intracytoplasmic sperm injection treatment; and prospectively study the influence of initial antimüllerian hormone (AMH) concentrat......OBJECTIVE: To evaluate the dose-response relationship of a novel recombinant human FSH (rhFSH; FE 999049) with respect to ovarian response in patients undergoing IVF/intracytoplasmic sperm injection treatment; and prospectively study the influence of initial antimüllerian hormone (AMH...

  5. Electron solvation and geminate ion recombination in ionic liquids

    International Nuclear Information System (INIS)

    The behavior of radiation-induced active species in ionic liquids attract much attention from view point of radiation induced decomposition and reaction in ionic liquids. The formation process, lifetime, yield and reactivity of solvated electrons were studied in alkyl ammonium ionic liquid by electron beam pulse radiolysis method. As a result, the G-value of the solvated electron is about 1, the lifetime is about 300 ns, the high efficiency reaction between the dry electron and solute were clarified. Most of the ionized electron would recombine with parent radical cation geminately. Pre-solvated electron reaction and geminate ion recombination were investigated using the femtosecond pulse radiolysis system. (author)

  6. Recombination among multiple mitochondrial pseudogenes from a passerine genus

    DEFF Research Database (Denmark)

    Nielsen, Kirstine Klitgaard; Arctander, P.

    2001-01-01

    PCR products of a fragment of the mitchondrial protein coding subunit 5 of NADH-dehydrogenase (ND5) from eight individuals representing five species of the South American bird genus Conirostrum were cloned. The 130 clones, which were subsequently sequenced, constituted 55 different sequences. Due...... to the observed differences in substitution patterns 58% of the cloned sequences were identified as pseudogenes. Recombination could be traced in 19% of the inferred nuclear pseudogenes, but this figure probably represents a Significant underestimation of the factual recombination events. The nonrecombined...

  7. Recombinant chromosome 18 resulting from a maternal pericentric inversion

    Energy Technology Data Exchange (ETDEWEB)

    Ayukawa, Hiroshi; Tsukahara, Masato; Fukuda, Masamichi; Kondoh, Osamu [Yamaguchi Univ. School of Medicine (Japan)

    1994-05-01

    We report on a newborn girl with duplication of 18q12.2{yields}18 qter and deficiency of 18p11.2{yields}18pter which resulted from meiotic recombination of the maternal pericentric inversion, inv(18)(p11.2q12.2). Her clinical manifestations were compatible with those of partial trisomy 18q syndrome. We review the previously reported 9 cases in 8 families of rec(18) resulting from recombination of a parental pericentric inversion. 8 refs., 3 figs., 1 tab.

  8. Photon Angular Distribution and Polarization of Radiative Recombination

    Institute of Scientific and Technical Information of China (English)

    OU Wei-Ying; SHEN Tian-Ming; CHEN Chong-Yang; Roger Hutton; ZOU Ya-Ming

    2005-01-01

    @@ A systematic study is carried out on the angular distribution and polarization of photons emitted following radiative-recombination of bare and He-like ions of Ne, Ar, Ni and Mo with a unidirectional electron beam. In order to incorporate the screening effect due to inner-shell electrons, a distorted wave method is used. Scaling rules for polarization of the photon following radiative recombination to both bare and He-like ions are given for the incident energy regions up to six times the ionization threshold energy of the final state.

  9. All-guided stellar interferometer with an integrated optics recombiner.

    Science.gov (United States)

    Huss, G; Schanen-Duport, L; Delage, L; Reynaud, F

    2001-06-01

    We report laboratory tests of an all-guided stellar interferometer used for optical aperture synthesis. In anticipation of use of the interferometer in space missions, this research is focused especially on compactness of the recombining device. The coherent transport and delay lines are implemented with polarization-maintaining fiber. Beam recombination is achieved by means of an integrated optics component. This two-arm interferometer operates at 670-nm mean wavelength and allows for a 24-cm correction for the differential air path. PMID:18040444

  10. Ig heavy chain class switch recombination: mechanism and regulation

    OpenAIRE

    Stavnezer, Janet; Schrader, Carol E.

    2014-01-01

    Ig heavy chain class switching occurs rapidly after activation of mature naïve B cells, resulting in a switch from expressing IgM and IgD to expression of IgG, IgE, or IgA; this switch improves the ability of antibodies to remove the pathogen that induces the humoral immune response. Class switching occurs by a deletional recombination between two different switch (S) regions, each of which is associated with a heavy chain constant (CH) region gene. Class switch recombination (CSR) is instiga...

  11. Influence of magnetic fields on recombination rates of Au25+

    International Nuclear Information System (INIS)

    Recombination of Au25+-ions has been investigated in a single-pass merged-beams experiment at the UNILAC of GSI in Darmstadt. Very low energies in the electron-ion center-of-mass frame were particularly addressed. At Erel = 0 eV we found a recombination rate exceeding the expectations by a factor of 365. For further investigation of this enhancement, the electron density and the magnetic field guiding the electron beam were varied. While an increase of the electron density by a factor of 10 had little influence, the measured rate coefficient increased significantly with the magnetic field strength. (orig.)

  12. A recombinant single chain antibody interleukin-2 fusion protein.

    OpenAIRE

    Savage, P; So, A; Spooner, R A; Epenetos, A. A.

    1993-01-01

    Recombinant interleukin-2 (rIL-2) therapy has been shown to be of value in the treatment of some cases of melanoma and renal cell carcinoma. However its use can be limited by severe systemic toxicity. Targeting rIL-2 to the tumour should improve the anti-tumour immune response and decrease the systemic toxicity. With this aim we have employed recombinant DNA techniques to construct a single chain antibody interleukin-2 fusion protein (SCA-IL-2). The protein used in this model system comprises...

  13. Hydrogen Recombination Rates of Plate-type Passive Auto-catalytic Recombiner

    International Nuclear Information System (INIS)

    The hydrogen mitigation system may include igniters, passive autocatalytic recombiner (PAR), and venting or dilution system. Recently PAR is commonly used as a main component of HMS in a NPP containment because of its passive nature. PARs are categorized by the shape and material of catalytic surface. Catalytic surface coated by platinum is mostly used for the hydrogen recombiners. The shapes of the catalytic surface can be grouped into plate type, honeycomb type and porous media type. Among them, the plate-type PAR is well tested by many experiments. PAR performance analysis can be approached by a multi-scale method which is composed of micro, meso and macro scales. The criterion of the scaling is the ratio of thickness of boundary layer developed on a catalytic surface to representative length of a computational domain. Mass diffusion in the boundary layer must be resolved in the micro scale analysis. In a lumped parameter (LP) analysis using a system code such as MAAP or MELCOR, the chamber of the PAR is much smaller than a computational node. The hydrogen depletion by a PAR is modeled as a source of mass and energy conservation equations. Te catalytic surface reaction of hydrogen must be modeled by a volume-averaged correlation. In this study, a micro scale analysis method is developed using libraries in OpenFOAM to evaluate a hydrogen depletion rate depending on parameters such as size and number of plates and plate arrangement. The analysis code is validated by simulating REKO-3 experiment. And hydrogen depletion analysis is conducted by changing the plate arrangement as a trial of the performance enhancement of a PAR. In this study, a numerical code for an analysis of a PAR performance in a micro scale has been developed by using OpenFOAM libraries. The physical and numerical models were validated by simulating the REKO-3 experiment. As a try to enhance the performance of the plate-type PAR, it was proposed to apply a staggered two-layer arrangement of the

  14. Hydrogen Recombination Rates of Plate-type Passive Auto-catalytic Recombiner

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongtae; Hong, Seong-Wan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Gun Hong [Kyungwon E-C Co., Seongnam (Korea, Republic of)

    2014-10-15

    The hydrogen mitigation system may include igniters, passive autocatalytic recombiner (PAR), and venting or dilution system. Recently PAR is commonly used as a main component of HMS in a NPP containment because of its passive nature. PARs are categorized by the shape and material of catalytic surface. Catalytic surface coated by platinum is mostly used for the hydrogen recombiners. The shapes of the catalytic surface can be grouped into plate type, honeycomb type and porous media type. Among them, the plate-type PAR is well tested by many experiments. PAR performance analysis can be approached by a multi-scale method which is composed of micro, meso and macro scales. The criterion of the scaling is the ratio of thickness of boundary layer developed on a catalytic surface to representative length of a computational domain. Mass diffusion in the boundary layer must be resolved in the micro scale analysis. In a lumped parameter (LP) analysis using a system code such as MAAP or MELCOR, the chamber of the PAR is much smaller than a computational node. The hydrogen depletion by a PAR is modeled as a source of mass and energy conservation equations. Te catalytic surface reaction of hydrogen must be modeled by a volume-averaged correlation. In this study, a micro scale analysis method is developed using libraries in OpenFOAM to evaluate a hydrogen depletion rate depending on parameters such as size and number of plates and plate arrangement. The analysis code is validated by simulating REKO-3 experiment. And hydrogen depletion analysis is conducted by changing the plate arrangement as a trial of the performance enhancement of a PAR. In this study, a numerical code for an analysis of a PAR performance in a micro scale has been developed by using OpenFOAM libraries. The physical and numerical models were validated by simulating the REKO-3 experiment. As a try to enhance the performance of the plate-type PAR, it was proposed to apply a staggered two-layer arrangement of the

  15. Productive homologous and non-homologous recombination of hepatitis C virus in cell culture.

    Directory of Open Access Journals (Sweden)

    Troels K H Scheel

    2013-03-01

    Full Text Available Genetic recombination is an important mechanism for increasing diversity of RNA viruses, and constitutes a viral escape mechanism to host immune responses and to treatment with antiviral compounds. Although rare, epidemiologically important hepatitis C virus (HCV recombinants have been reported. In addition, recombination is an important regulatory mechanism of cytopathogenicity for the related pestiviruses. Here we describe recombination of HCV RNA in cell culture leading to production of infectious virus. Initially, hepatoma cells were co-transfected with a replicating JFH1ΔE1E2 genome (genotype 2a lacking functional envelope genes and strain J6 (2a, which has functional envelope genes but does not replicate in culture. After an initial decrease in the number of HCV positive cells, infection spread after 13-36 days. Sequencing of recovered viruses revealed non-homologous recombinants with J6 sequence from the 5' end to the NS2-NS3 region followed by JFH1 sequence from Core to the 3' end. These recombinants carried duplicated sequence of up to 2400 nucleotides. HCV replication was not required for recombination, as recombinants were observed in most experiments even when two replication incompetent genomes were co-transfected. Reverse genetic studies verified the viability of representative recombinants. After serial passage, subsequent recombination events reducing or eliminating the duplicated region were observed for some but not all recombinants. Furthermore, we found that inter-genotypic recombination could occur, but at a lower frequency than intra-genotypic recombination. Productive recombination of attenuated HCV genomes depended on expression of all HCV proteins and tolerated duplicated sequence. In general, no strong site specificity was observed. Non-homologous recombination was observed in most cases, while few homologous events were identified. A better understanding of HCV recombination could help identification of natural

  16. Mediation of surface recombination in a II-VI powder by palladium microislands

    Science.gov (United States)

    Sahyun, M. R. V.

    1987-04-01

    The recombination mechanisms in a Zn(Cd)S:Ag phosphor powder have been probed by luminescence and flash-photolysis time-resolved dielectric loss techniques. The influence of Pd-microislands chemically deposited thereon, alone, and in conjunction with recombination mediators phenylhydrazine and phenylacetic acid (in xylene solution) on the recombination pathways was studied. The Pd deposit affects recombination by increasing the fraction of the particle volume dominated by the surface processes, by providing a pathway for photoelectrons to reach the (negative) surface to participate in surface recombination, and by providing recombination centers per se. The implications of these results for heterogeneous photocatalysis are discussed.

  17. Sum rules for meson and baryon production in the quark recombination model

    International Nuclear Information System (INIS)

    A quark-recombination model with quark distributions according to a generalized Kuti-Weisskopf model is used. Mesons are formed by v-s (valence-sea) and s-s recombination, baryons by vvv, vvs, vss and sss recombination. Sum rules for energy momentum conservation, baryon number, valence and sea quarks are shown to constrain the recombination parameters of the model significantly. The resulting model is consistent with experimental data. While the sss recombination into baryons is found to be quite normal we find a strong enhancement of ss recombination into mesons. This enhanced ss term represents in the model the central meson production via gluons. (author)

  18. High-Resolution Mapping of Homologous Recombination Events in rad3 Hyper-Recombination Mutants in Yeast.

    Directory of Open Access Journals (Sweden)

    Sabrina L Andersen

    2016-03-01

    Full Text Available The Saccharomyces cerevisae RAD3 gene is the homolog of human XPD, an essential gene encoding a DNA helicase of the TFIIH complex involved in both nucleotide excision repair (NER and transcription. Some mutant alleles of RAD3 (rad3-101 and rad3-102 have partial defects in DNA repair and a strong hyper-recombination (hyper-Rec phenotype. Previous studies showed that the hyper-Rec phenotype associated with rad3-101 and rad3-102 can be explained as a consequence of persistent single-stranded DNA gaps that are converted to recombinogenic double-strand breaks (DSBs by replication. The systems previously used to characterize the hyper-Rec phenotype of rad3 strains do not detect the reciprocal products of mitotic recombination. We have further characterized these events using a system in which the reciprocal products of mitotic recombination are recovered. Both rad3-101 and rad3-102 elevate the frequency of reciprocal crossovers about 100-fold. Mapping of these events shows that three-quarters of these crossovers reflect DSBs formed at the same positions in both sister chromatids (double sister-chromatid breaks, DSCBs. The remainder reflects DSBs formed in single chromatids (single chromatid breaks, SCBs. The ratio of DSCBs to SCBs is similar to that observed for spontaneous recombination events in wild-type cells. We mapped 216 unselected genomic alterations throughout the genome including crossovers, gene conversions, deletions, and duplications. We found a significant association between the location of these recombination events and regions with elevated gamma-H2AX. In addition, there was a hotspot for deletions and duplications at the IMA2 and HXT11 genes near the left end of chromosome XV. A comparison of these data with our previous analysis of spontaneous mitotic recombination events suggests that a sub-set of spontaneous events in wild-type cells may be initiated by incomplete NER reactions, and that DSCBs, which cannot be repaired by sister

  19. Antithrombin III for critically ill patients

    DEFF Research Database (Denmark)

    Allingstrup, Mikkel; Wetterslev, Jørn; Ravn, Frederikke B;

    2016-01-01

    no statistically significant effect of AT III on mortality (RR 0.95, 95% CI 0.88-1.03, I (2) = 0%, fixed-effect model, 29 trials, 3882 participants). Among those with severe sepsis and disseminated intravascular coagulation (DIC), AT III showed no impact on mortality (RR 0.95, 95% Cl 0.88-1.03, I (2) = 0%, fixed...

  20. Registration of 'RU9101001'/'Katy' recombinant inbred lines of rice

    Science.gov (United States)

    The cross of RU9101001/'Katy' rice (Oryza sativa L.) was used to develop a mapping population consisting of 238 F9 generation recombinant inbred lines of rice (Oryza sativa L.) (GSOR100361 to GSOR100600). This population has been used to map major genes that provide resistance to the rice blast pat...

  1. Activity of recombinant factor VIIa under different conditions in vitro

    DEFF Research Database (Denmark)

    Bladbjerg, Else-Marie; Jespersen, Jørgen

    2008-01-01

    Recombinant activated factor VII (NovoSeven; Novo Nordisk A/S, Måløv, Denmark) is an effective drug for treatment of bleeding in patients with haemophilia A or B and inhibitors. Little is known about physiological conditions influencing the efficacy of recombinant activated factor VII. We...... investigated the in-vitro effects of pH, temperature, and haemodilution on the activity of recombinant activated factor VII. Samples from eight healthy volunteers were spiked with recombinant activated factor VII (final concentration 1.7 microg/ml) and adjusted to pH 6.0, 6.5, 7.0, and 7.4 or analysed at 30...... activity in plasma. Significant effects of pH were observed for clotting time, clot formation time, maximum clot firmness, and factor VII coagulant activity in the direction of longer clot formation times and less firm clots with decreasing pH. Temperature had significant effects on clotting time, clot...

  2. Genetic recombination in Actinoplanes brasiliensis by protoplast fusion.

    OpenAIRE

    Palleroni, N. J.

    1983-01-01

    Protoplast formation, fusion, and cell regeneration have been achieved with mutant strains of Actinoplanes brasiliensis. Three-, four-, and five-factor crosses have shown genetic recombination among the markers, and a five-factor cross is analyzed and discussed. Possibilities of using protoplast fusion for gene mapping and strain improvement are suggested.

  3. Recent advances in yeast molecular biology: recombinant DNA. [Lead abstract

    Energy Technology Data Exchange (ETDEWEB)

    1982-09-01

    Separate abstracts were prepared for the 25 papers presented at a workshop focusing on chromosomal structure, gene regulation, recombination, DNA repair, and cell type control, that have been obtained by experimental approaches incorporating the new technologies of yeast DNA transformation, molecular cloning, and DNA sequence analysis. (KRM)

  4. Experimental investigation of ion-ion recombination at atmospheric conditions

    OpenAIRE

    A. Franchin; S. Ehrhart; Leppä, J.; Nieminen, T.; Gagné, S.; Schobesberger, S.; D. Wimmer; J. Duplissy; Riccobono, F.; Dunne, E; L. Rondo; Downard, A.; BIANCHI, F.; Kupc, A.; Tsagkogeorgas, G.

    2015-01-01

    We present the results of laboratory measurements of the ion-ion recombination coefficient at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at CERN, the walls of which are made of conductive material, making it possible to measure s...

  5. Treatment of anemia of nephrotic syndrome with recombinant erythropoietin

    NARCIS (Netherlands)

    Gansevoort, RT; Vaziri, ND; deJong, PE

    1996-01-01

    Nephrotic syndrome has been recently shown to cause erythropoietin (EPO) deficiency in humans and experimental models. However, efficacy and safety of recombinant EPO (rEPO) in the treatment of the associated anemia has not been previously investigated. We report a patient with nephrotic syndrome an

  6. Haemostatic aspects of recombinant human erythropoietin in colorectal surgery

    DEFF Research Database (Denmark)

    Poulsen, K A; Qvist, N; Winther, K;

    1998-01-01

    OBJECTIVE: To find out whether recombinant human erythropoietin (r-HuEPO) given perioperatively has any effect on haemostatic activity in patients undergoing elective colorectal resection. DESIGN: A placebo-controlled double-blind study. SETTING: Odense university hospital, Denmark. SUBJECTS: 24...

  7. The electron-ionized donor recombination in semiconductors

    International Nuclear Information System (INIS)

    A calculation is presented of the recombination cross section of a conduction electron and a donor impurity. Donor states are described in a many-valley model. It is shown that, for Si, the main contribution comes from the intravalley terms and that the intervalley terms are completely negligible. (author)

  8. Recombination facilitates neofunctionalization of duplicate genes via originalization

    Directory of Open Access Journals (Sweden)

    Huang Ren

    2010-06-01

    Full Text Available Abstract Background Recently originalization was proposed to be an effective way of duplicate-gene preservation, in which recombination provokes the high frequency of original (or wild-type allele on both duplicated loci. Because the high frequency of wild-type allele might drive the arising and accumulating of advantageous mutation, it is hypothesized that recombination might enlarge the probability of neofunctionalization (Pneo of duplicate genes. In this article this hypothesis has been tested theoretically. Results Results show that through originalization recombination might not only shorten mean time to neofunctionalizaiton, but also enlarge Pneo. Conclusions Therefore, recombination might facilitate neofunctionalization via originalization. Several extensive applications of these results on genomic evolution have been discussed: 1. Time to nonfunctionalization can be much longer than a few million generations expected before; 2. Homogenization on duplicated loci results from not only gene conversion, but also originalization; 3. Although the rate of advantageous mutation is much small compared with that of degenerative mutation, Pneo cannot be expected to be small.

  9. Links between replication, recombination and genome instability in eukaryotes

    OpenAIRE

    Flores-Rozas, Hernan; Kolodner, Richard D.

    2000-01-01

    Double-strand breaks in DNA can be repaired by homologous recombination including break-induced replication. In this reaction, the end of a broken DNA invades an intact chromosome and primes DNA replication resulting in the synthesis of an intact chromosome. Break-induced replication has also been suggested to cause different types of genome rearrangements.

  10. Recent advances in yeast molecular biology: recombinant DNA

    International Nuclear Information System (INIS)

    Separate abstracts were prepared for the 25 papers presented at a workshop focusing on chromosomal structure, gene regulation, recombination, DNA repair, and cell type control, that have been obtained by experimental approaches incorporating the new technologies of yeast DNA transformation, molecular cloning, and DNA sequence analysis

  11. Modelling of the aerosol deposition in a hydrogen catalytic recombiner

    Energy Technology Data Exchange (ETDEWEB)

    Vendel, J.; Studer, E.; Zavaleta, P. [Inst. de Protection et de Surete Nucleaire, Dept. de Prevention et d' Etudes des Accidents, Gif-sur-Yvette Cedex (France); Hadida, Ph. [Quasar Informatique, Paris (France)

    1997-03-01

    Catalytic recombiners are used to remove the hydrogen released in case of a severe accident in a nuclear power plant, so as to reduce the risk of deflagration or detonation. H{sub 2}PAR experiments are carried out to precise the behaviour of recombiners in term of poisoning by aerosols. Firstly, some calculations have been done with the Trio-EF code to assess the structure of convection loops in the experimental tent. We note that when the recombiner is active, it may have a strong influence on the flow inside the tent and may even interact with an other heat source such as a furnace. In the second part, we study the deposition of aerosols on catalytic plates for a given recombiner, when it is active or passive. We list the different mechanisms and quantify them by introducing the deposition velocity. In fact, thermophoresis appears to be the main mechanism, compared to brownian diffusion or difrusiophoresis, which governs aerosols deposition. It favours deposition on <> plates and acts against it for <> plates. (author)

  12. A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner

    Directory of Open Access Journals (Sweden)

    Rożeń Antoni

    2015-03-01

    Full Text Available : A passive autocatalytic hydrogen recombiner (PAR is a self-starting device, without operator action or external power input, installed in nuclear power plants to remove hydrogen from the containment building of a nuclear reactor. A new mechanistic model of PAR has been presented and validated by experimental data and results of Computational Fluid Dynamics (CFD simulations. The model allows to quickly and accurately predict gas temperature and composition, catalyst temperature and hydrogen recombination rate. It is assumed in the model that an exothermic recombination reaction of hydrogen and oxygen proceeds at the catalyst surface only, while processes of heat and mass transport occur by assisted natural and forced convection in non-isothermal and laminar gas flow conditions in vertical channels between catalyst plates. The model accounts for heat radiation from a hot catalyst surface and has no adjustable parameters. It can be combined with an equation of chimney draft and become a useful engineering tool for selection and optimisation of catalytic recombiner geometry.

  13. Experimental studies on catalytic hydrogen recombiners for light water reactors

    International Nuclear Information System (INIS)

    In the course of core melt accidents in nuclear power plants a large amount of hydrogen can be produced and form an explosive or even detonative gas mixture with aerial oxygen in the reactor building. In the containment atmosphere of pressurized water reactors hydrogen combines a phlogistically with the oxygen present to form water vapor even at room temperature. In the past, experimental work conducted at various facilities has contributed little or nothing to an understanding of the operating principles of catalytic recombiners. Hence, the purpose of the present study was to conduct detailed investigations on a section of a recombiner essentially in order to deepen the understanding of reaction kinetics and heat transport processes. The results of the experiments presented in this dissertation form a large data base of measurements which provides an insight into the processes taking place in recombiners. The reaction-kinetic interpretation of the measured data confirms and deepens the diffusion theory - proposed in an earlier study. Thus it is now possible to validate detailed numeric models representing the processes in recombiners. Consequently the present study serves to broaden and corroborate competence in this significant area of reactor technology. In addition, the empirical knowledge thus gained may be used for a critical reassessment of previous numeric model calculations. (orig.)

  14. Structural characterization of recombinant therapeutic proteins by circular dichroism.

    Science.gov (United States)

    Bertucci, Carlo; Pistolozzi, Marco; De Simone, Angela

    2011-10-01

    Most of the protein therapeutics are now produced by recombinant DNA technology. The advantages of recombinant proteins are related to their higher specificity and to their safety as exposure to animal or human diseases. However, several problems are still present in development of recombinant proteins as therapeutics, such as low bioavailability, short serum half-life, and immune response. Their successful application hinges on the protein stereochemical stability, and on the folding and the tendency to aggregate induced by purification steps and storage. All these aspects determine the failure of many potential protein therapies, and limitations in the development of the formulation. The application of multiple analytical techniques is important in order to obtain a detailed product profile and to understand how manufacturing can influence product structure and activity. Surely the protein conformation is a key aspect to be assessed, because a specific conformation is often essential for the biological function of the protein. Thus, there is a growing need to perform structural studies under the conditions in which the proteins operate, and to monitor the structural changes of the protein. Circular dichroism has been increasingly recognised as a valuable and reliable technique to get this information. In particular, examples will be here reported on the use of circular dichroism spectroscopy in the structural characterization of free and formulated recombinant proteins, looking at the prediction of the secondary structure, propensity to conformational changes, stability, and tendency to aggregate.

  15. [Asymmetric biosynthesis of d-pseudoephedrine by recombinant Bacillus subtilis].

    Science.gov (United States)

    Peng, Yanhong; Zhang, Liang; Ding, Zhongyang; Wang, Zhengxiang; Shi, Guiyang

    2011-07-01

    In order to successfully express the carbonyl reductase gene mldh in Bacillus subtilis and complete coenzyme regeneration by B. subtilis glucose dehydrogenase, the promoter PrpsD and the terminator TrpsD from B. subtilis rpsD gene were used as the expression cassette to be a recombinant plasmid pHY300plk-PrpsD-TrpsD. After that, the carbonyl reductase gene mldh was inserted into the previous plasmid and a plasmid pHY300plk-PrpsD-mldh-TrpsD was achieved, followed by transformed into B. subtilis Wb600 to obtain a recombinant B. subtilis Wb600 (pHY300plk-PrpsD-mldh-TrpsD). Subsequently, the results for whole-cell biotransformation from recombinant B. subtilis showed that it could be used to catalyze MAK (1-phenyl- 1-keto-2-methylaminopropane) to d-pseudoephedrine in the presence of glucose. The yield of d-pseudoephedrine could be up to 97.5 mg/L and the conversion rate of MAK was 24.1%. This study indicates the possibility of biotransformation production of d-pseudoephedrine from recombinant B. subtilis.

  16. Metabolic adaptation in transplastomic plants massively accumulating recombinant proteins.

    Directory of Open Access Journals (Sweden)

    Julia Bally

    Full Text Available BACKGROUND: Recombinant chloroplasts are endowed with an astonishing capacity to accumulate foreign proteins. However, knowledge about the impact on resident proteins of such high levels of recombinant protein accumulation is lacking. METHODOLOGY/PRINCIPAL FINDINGS: Here we used proteomics to characterize tobacco (Nicotiana tabacum plastid transformants massively accumulating a p-hydroxyphenyl pyruvate dioxygenase (HPPD or a green fluorescent protein (GFP. While under the conditions used no obvious modifications in plant phenotype could be observed, these proteins accumulated to even higher levels than ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco, the most abundant protein on the planet. This accumulation occurred at the expense of a limited number of leaf proteins including Rubisco. In particular, enzymes involved in CO(2 metabolism such as nuclear-encoded plastidial Calvin cycle enzymes and mitochondrial glycine decarboxylase were found to adjust their accumulation level to these novel physiological conditions. CONCLUSIONS/SIGNIFICANCE: The results document how protein synthetic capacity is limited in plant cells. They may provide new avenues to evaluate possible bottlenecks in recombinant protein technology and to maintain plant fitness in future studies aiming at producing recombinant proteins of interest through chloroplast transformation.

  17. Doping in the recombinant era: strategies and counterstrategies.

    Science.gov (United States)

    Azzazy, Hassan M E; Mansour, Mai M H; Christenson, Robert H

    2005-11-01

    Advances in recombinant DNA technology have created one of the most powerful weapons in the current doping arsenal: recombinant proteins [Sweeney HL. Gene doping. Sci Am 2004;291:62-9; Unal M, Ozer Unal D. Gene doping in sports. Sports Med 2004;34:357-62]. Recombinant erythropoietin (EPO) and human growth hormone (hGH) are currently being abused but are fortunately detectable either directly by employing isoelectric focusing and immunoassays or indirectly by assessing changes in selected hematopoietic parameters. The detection is technically demanding due to the extent of similarity between the recombinant proteins and their endogenous counterparts. Another issue facing detection efforts is the speed and conditions at which blood samples are collected and analyzed in a sports setting. Recently, gene doping, which stemmed out of legitimate gene therapy trials, has emerged as the next level of doping. Erythropoietin (EPO), human growth hormone (hGH), insulin-like growth factor-1 (IGF-1), peroxisome proliferator-activated receptor-delta (PPAR delta), and myostatin inhibitor genes have been identified as primary targets for doping. Sports clinical scientists today are racing against the clock because assuring the continued integrity of sports competition depends on their ability to outpace the efforts of dopers by developing new detection strategies. PMID:16286094

  18. A Collaborative, Investigative Recombinant DNA Technology Course with Laboratory

    Science.gov (United States)

    Pezzementi, Leo; Johnson, Joy F.

    2002-01-01

    A recombinant DNA technology course was designed to promote contextual, collaborative, inquiry-based learning of science where students learn from one another and have a sense of ownership of their education. The class stressed group presentations and critical reading and discussion of scientific articles. The laboratory consisted of two research…

  19. Recombinant Human Erythropoietin in the Treatment of Acute Ischemic Stroke

    NARCIS (Netherlands)

    Ehrenreich, Hannelore; Weissenborn, Karin; Prange, Hilmar; Schneider, Dietmar; Weimar, Christian; Wartenberg, Katja; Schellinger, Peter D.; Bohn, Matthias; Becker, Harald; Wegrzyn, Martin; Jaehnig, Peter; Herrmann, Manfred; Knauth, Michael; Baehr, Mathias; Heide, Wolfgang; Wagner, Armin; Schwab, Stefan; Reichmann, Heinz; Schwendemann, Guenther; Dengler, Reinhard; Kastrup, Andreas; Bartels, Claudia

    2009-01-01

    Background and Purpose-Numerous preclinical findings and a clinical pilot study suggest that recombinant human erythropoietin (EPO) provides neuroprotection that may be beneficial for the treatment of patients with ischemic stroke. Although EPO has been considered to be a safe and well-tolerated dru

  20. The many facets of homologous recombination at telomeres

    Directory of Open Access Journals (Sweden)

    Clémence Claussin

    2015-07-01

    Full Text Available The ends of linear chromosomes are capped by nucleoprotein structures called telomeres. A dysfunctional telomere may resemble a DNA double-strand break (DSB, which is a severe form of DNA damage. The presence of one DSB is sufficient to drive cell cycle arrest and cell death. Therefore cells have evolved mechanisms to repair DSBs such as homologous recombination (HR. HR-mediated repair of telomeres can lead to genome instability, a hallmark of cancer cells, which is why such repair is normally inhibited. However, some HR-mediated processes are required for proper telomere function. The need for some recombination activities at telomeres but not others necessitates careful and complex regulation, defects in which can lead to catastrophic consequences. Furthermore, some cell types can maintain telomeres via telomerase-independent, recombination-mediated mechanisms. In humans, these mechanisms are called alternative lengthening of telomeres (ALT and are used in a subset of human cancer cells. In this review, we summarize the different recombination activities occurring at telomeres and discuss how they are regulated. Much of the current knowledge is derived from work using yeast models, which is the focus of this review, but relevant studies in mammals are also included.

  1. Theory of a cw supersonic nitrogen recombination laser

    International Nuclear Information System (INIS)

    Quasi-two dimensional model calculations show the possibility to realize a cw atomic nitrogen laser, pumped by the recombination process in rapidly expanded plasma flows. Sufficient gain for lasing is demontrated for stagnation conditions of 13 000 00-1 can be attained. The model is described and some selected results are presented. The effect of the electron heat conduction is discussed

  2. Dielectronic recombination of Fe^{13+}: benchmarking the M-shell

    CERN Document Server

    Badnell, N R

    2006-01-01

    We have carried-out a series of multi-configuration Breit-Pauli AUTOSTRUCTURE calculations for the dielectronic recombination of Fe^{13+}. We present a detailed comparison of the results with the high-energy resolution measurements reported recently from the Heidelberg Test Storage Ring by Schmidt et al. Many Rydberg series contribute significantly from this initial 3s^2 3p M-shell ion, resulting in a complex recombination `spectrum'. While there is much close agreement between theory and experiment, differences of typically 50% in the summed resonance strengths over 0.1-10 eV result in the experimentally based total Maxwellian recombination rate coefficient being a factor of 1.52-1.38 larger than theory over 10^4-10^5 K, which is a typical temperature range of peak abundance for Fe^{13+} in a photoionized plasma. Nevertheless, this theoretical recombination rate coefficient is an order of magnitude larger than that used by modellers to-date. This may help explain the discrepancy between the iron M-shell ioni...

  3. Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Gorman, C.M.; Moffat, L.F.; Howard, B.H.

    1982-09-01

    The authors constructed a series of recombinant genomes which directed expression of the enzyme chloramphenicol acetyltransferase (CAT) in mammalian cells. The prototype recombinant in this series, pSV2-cat, consisted of the beta-lactamase gene and origin of replication from pBR322 coupled to a simian virus 40 (SV40) early transcription region into which CAT coding sequences were inserted. Readily measured levels of CAT accumulated within 48 h after the introduction of pSV2-cat DNA into African green monkey kidney CV-1 cells. Because endogenous CAT activity is not present in CV-1 or other mammalian cells, and because rapid, sensitive assays for CAT activity are available, these recombinants provided a uniquely convenient system for monitoring the expression of foreign DNAs in tissue culture cells. To demonstrate the usefulness of this system, we constructed derivatives of pSV2-cat from which part or all of the SV 40 promoter region was removed. Deletion of one copy of the 72-base-pair repeat sequence in the SV40 promoter caused no significant decrease in CAT synthesis in monkey kidney CV-1 cells; however, an additional deletion of 50 base pairs from the second copy of the repeats reduced CAT synthesis to 11% of its level in the wild type. They also constructed a recombinant, pSVO-cat, in which the entire SV40 promoter region was removed and a unique HindIII site was substituted for the insertion of other promoter sequences.

  4. Recombination patterns reveal information about centromere location on linkage maps

    DEFF Research Database (Denmark)

    Limborg, Morten T.; McKinney, Garrett J.; Seeb, Lisa W.;

    2016-01-01

    . mykiss) characterized by low and unevenly distributed recombination – a general feature of male meiosis in many species. Further, a high frequency of double crossovers along chromosome arms in barley reduced resolution for locating centromeric regions on most linkage groups. Despite these limitations...

  5. Meiotic sister chromatid cohesion and recombination in two filamentous fungi

    NARCIS (Netherlands)

    Heemst, van D.

    2000-01-01

    Homologous recombination and sister chromatid cohesion play important roles in the maintenance of genome integrity and the fidelity of chromosome segregation in mitosis and meiosis. Within the living cell, the integrity of the DNA is threatened by various factors that cause DNA-lesions, of which DNA

  6. Recombineering using RecET from Pseudomonas syringae

    Science.gov (United States)

    Here we report the identification of functions that promote genomic recombination of linear DNA introduced into Pseudomonas cells by electroporation. The genes encoding these functions were identified in Pseudomonas syringae pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecE...

  7. A recombinant vaccinia virus expressing human carcinoembryonic antigen (CEA).

    Science.gov (United States)

    Kaufman, H; Schlom, J; Kantor, J

    1991-07-30

    Carcinoembryonic antigen (CEA) is a 180-kDa glycoprotein expressed on most gastrointestinal carcinomas. A 2.4-kb cDNA clone, containing the complete coding sequence, was isolated from a human colon tumor cell library and inserted into a vaccinia virus genome. This newly developed construct was characterized by Southern blotting, DNA hybridization studies, and polymerase chain reaction analysis. The CEA gene was stably integrated into the vaccinia virus thymidine kinase gene. The recombinant was efficiently replicated upon serial passages in cell cultures and in animals. The recombinant virus expresses on the surface of infected cells a protein product recognized by a monoclonal antibody (COL-I) directed against CEA. Immunization of mice with the vaccinia construct elicited a humoral immune response against CEA. Pilot studies also showed that administration of the recombinant CEA vaccinia construct was able to greatly reduce the growth in mice of a syngeneic murine colon adenocarcinoma which had been transduced with the human CEA gene. The use of this new recombinant CEA vaccinia construct may thus provide an approach in the specific active immunotherapy of human GI cancer and other CEA expressing carcinoma types.

  8. Review of literature on catalytic recombination of hydrogen--oxygen

    International Nuclear Information System (INIS)

    The results are reported of a literature search for information concerning the heterogeneous, gas phase, catalytic hydrogen-oxygen recombination. Laboratory scale experiments to test the performance of specific metal oxide catalysts under conditions simulating the atmosphere within a nuclear reactor containment vessel following a loss-of-coolant blowdown accident are suggested

  9. Ion-electron recombination in merged-beams experiments

    International Nuclear Information System (INIS)

    In the present thesis, studies of recombination processes applying the technique of merged beams of fast ions and electrons are described. The main advantage of this technique is that the low relative velocity of ions and electrons necessary for these investigations can be achieved, at the same time as the velocity of the ions relative to the molecules of the residual gas is high. The high ion velocity leads to a very low reaction cross section for the leading contribution to the background signal, the capture of electrons in collisions with residual gas molecules. The experimental technique is described, emphasizing the electron beam velocity distribution and its relation to the energy resolution of the experiments. The presentation of the process of electron cooling is aimed at introducing this process as a tool for merged-beams experiments in storage rings rather than investigating the process itself. The non-resonant process of radiative recombination for non-fully stripped ions, showing evidence of incomplete screening is presented. Experimental investigation of dielectronic recombination is presented. Results of measurements of this process for He-like ions form the Aarhus single-pass experiment and the Heidelberg storage ring experiment are compared. Recombination is reduced from being the aim of the investigation to being a tool for high-precision measurements of the lifetimes of the 1s2s 3S metastable states of HE-like ions of boron, carbon, and nitrogen, performed at the Heidelberg storage ring. The experiment is concerned with the process of dissociative recombination of molecular hydrogen ions. The discussion of this experiment emphasizes the distribution of population on the different vibrational levels of the ions in the initial state. In particular, a laser photo-dissociation technique was introduced to reduce the number of initial levels in the experiment. (EG) 24 refs

  10. Effective conductance method for the primordial recombination spectrum

    Science.gov (United States)

    Ali-Haïmoud, Yacine

    2013-01-01

    As atoms formed for the first time during primordial recombination, they emitted bound-bound and free-bound radiation leading to spectral distortions to the cosmic microwave background. These distortions might become observable in the future with high-sensitivity spectrometers, and provide a new window into physical conditions in the early universe. The standard multilevel atom method habitually used to compute the recombination spectrum is computationally expensive, impeding a detailed quantitative exploration of the information contained in spectral distortions thus far. In this work it is shown that the emissivity in optically thin allowed transitions can be factored into a computationally expensive but cosmology-independent part and a computationally cheap, cosmology-dependent part. The slow part of the computation consists in pre-computing temperature-dependent effective “conductances,” linearly relating line or continuum intensity to departures from Saha equilibrium of the lowest-order excited states (2s and 2p), that can be seen as “voltages.” The computation of these departures from equilibrium as a function of redshift is itself very fast, thanks to the effective multilevel atom method introduced in an earlier work. With this factorization, the recurring cost of a single computation of the recombination spectrum is only a fraction of a second on a standard laptop, more than four orders of magnitude shorter than standard computations. The spectrum from helium recombination can be efficiently computed in an identical way, and a fast code computing the full primordial recombination spectrum with this method will be made publicly available soon.

  11. Experimental investigation of ion-ion recombination at atmospheric conditions

    Directory of Open Access Journals (Sweden)

    A. Franchin

    2015-02-01

    Full Text Available We present the results of laboratory measurements of the ion-ion recombination coefficient at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the Cosmics Leaving OUtdoor Droplets (CLOUD chamber at CERN, the walls of which are made of conductive material, making it possible to measure small ions. We produced ions in the chamber using a 3.5 GeV c−1 beam of positively-charged pions (π+ from the CERN Proton Synchrotron (PS and with galactic cosmic rays, when the PS was switched off. The range of the ion production rate varied from 2 to 100 cm−3s−1, covering the typical range of ionization throughout the troposphere. The temperature ranged from −55 to 20 °C, the relative humidity from 0 to 70%, the SO2 concentration from 0 to 40 ppb, and the ozone concentration from 200 to 700 ppb. At 20 °C and 40% RH, the retrieved ion-ion recombination coefficient was (2.3 ± 0.7 × 10−6cm3s−1. We observed no dependency of the ion-ion recombination coefficient on ozone concentration and a weak variation with sulfur dioxide concentration. However, we found a strong dependency of the ion-ion recombination coefficient on temperature. We compared our results with three different models and found an overall agreement for temperatures above 0 °C, but a disagreement at lower temperatures. We observed a strong dependency of the recombination coefficient on relative humidity, which has not been reported previously.

  12. Insertion DNA Accelerates Meiotic Interchromosomal Recombination in Arabidopsis thaliana.

    Science.gov (United States)

    Sun, Xiao-Qin; Li, Ding-Hong; Xue, Jia-Yu; Yang, Si-Hai; Zhang, Yan-Mei; Li, Mi-Mi; Hang, Yue-Yu

    2016-08-01

    Nucleotide insertions/deletions are ubiquitous in eukaryotic genomes, and the resulting hemizygous (unpaired) DNA has significant, heritable effects on adjacent DNA. However, little is known about the genetic behavior of insertion DNA. Here, we describe a binary transgenic system to study the behavior of insertion DNA during meiosis. Transgenic Arabidopsis lines were generated to carry two different defective reporter genes on nonhomologous chromosomes, designated as "recipient" and "donor" lines. Double hemizygous plants (harboring unpaired DNA) were produced by crossing between the recipient and the donor, and double homozygous lines (harboring paired DNA) via self-pollination. The transfer of the donor's unmutated sequence to the recipient generated a functional β-glucuronidase gene, which could be visualized by histochemical staining and corroborated by polymerase chain reaction amplification and sequencing. More than 673 million seedlings were screened, and the results showed that meiotic ectopic recombination in the hemizygous lines occurred at a frequency  >6.49-fold higher than that in the homozygous lines. Gene conversion might have been exclusively or predominantly responsible for the gene correction events. The direct measurement of ectopic recombination events provided evidence that an insertion, in the absence of an allelic counterpart, could scan the entire genome for homologous counterparts with which to pair. Furthermore, the unpaired (hemizygous) architectures could accelerate ectopic recombination between itself and interchromosomal counterparts. We suggest that the ectopic recombination accelerated by hemizygous architectures may be a general mechanism for interchromosomal recombination through ubiquitously dispersed repeat sequences in plants, ultimately contributing to genetic renovation and eukaryotic evolution. PMID:27189569

  13. Recombination in the human Pseudoautosomal region PAR1.

    Science.gov (United States)

    Hinch, Anjali G; Altemose, Nicolas; Noor, Nudrat; Donnelly, Peter; Myers, Simon R

    2014-07-01

    The pseudoautosomal region (PAR) is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this obligatory crossover occurs remains unknown, as does the fine-scale positioning of crossovers across this region. Recent research in mice has suggested that crossovers in PAR may be mediated independently of the protein PRDM9, which localises virtually all crossovers in the autosomes. To investigate recombination in this region, we construct the most fine-scale genetic map containing directly observed crossovers to date using African-American pedigrees. We leverage recombination rates inferred from the breakdown of linkage disequilibrium in human populations and investigate the signatures of DNA evolution due to recombination. Further, we identify direct PRDM9 binding sites using ChIP-seq in human cells. Using these independent lines of evidence, we show that, in contrast with mouse, PRDM9 does localise peaks of recombination in the human PAR1. We find that recombination is a far more rapid and intense driver of sequence evolution in PAR1 than it is on the autosomes. We also show that PAR1 hotspot activities differ significantly among human populations. Finally, we find evidence that PAR1 hotspot positions have changed between human and chimpanzee, with no evidence of sharing among the hottest hotspots. We anticipate that the genetic maps built and validated in this work will aid research on this vital and fascinating region of the genome. PMID:25033397

  14. CFD analysis of passive autocatalytic recombiner interaction with atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Gera, B.; Sharma, Pavan K.; Singh, R.K.; Vaze, K.K. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Safety Div.

    2011-05-15

    In water cooled power reactors, significant quantities of hydrogen could be produced following a severe accident (loss-of coolant-accident along with non availability of Emergency Core Cooling System) from the reaction between steam and zirconium at high fuel clad temperature. In order to prevent the containment and other safety relevant components from incurring serious damage caused by a detonation of the hydrogen/air-mixture generated during a severe accident in water cooled power reactors, passive autocatalytic recombiners (PAR) are used for hydrogen removal in an increasing number of French, German and Russian plants. These devices make use of the fact that hydrogen and oxygen react exothermally on catalytic surfaces generating steam and heat. Numerous tests and simulations have been conducted in the past to investigate passive autocatalytic recombiners behaviour in situations representative of severe accidents. Numerical models were developed from the experimental data for codes like COCOSYS or ASTEC in order to optimise the passive autocatalytic recombiners location and to assess the efficiency of passive autocatalytic recombiners implementation in different scenarios. However, these models are usually simple (black-box type) and based on the manufacturer's correlation to calculate the hydrogen depletion rate. Recently, uses of enhanced CFD models have shown significant improvements towards modeling such phenomenon in complex geometry. The work presents CFD analysis of interaction of a representative nuclear power plant containment atmosphere with passive autocatalytic recombiners simulated using the commercial Computational Fluid Dynamics code for PAR Interaction Studies (PARIS benchmarks) exercise. A two-dimensional geometrical model of the simulation domain was used. The containment was represented by an adiabatic rectangular box with two PAR located at intermediate elevations near opposite walls. The flow in the simulation domain was modelled as

  15. Multiple genomic recombination events in the evolution of saffold cardiovirus.

    Directory of Open Access Journals (Sweden)

    Lili Ren

    Full Text Available BACKGROUND: Saffold cardiovirus (SAFV is a new human cardiovirus with 11 identified genotypes. Little is known about the natural history and pathogenicity of SAFVs. METHODOLOGY/PRINCIPAL FINDINGS: We sequenced the genome of five SAFV-1 strains which were identified from fecal samples taken from children with viral diarrhea in Beijing, China between March 2006 and November 2007, and analyzed the phylogenetic and phylodynamic properties of SAFVs using the genome sequences of every known SAFV genotypes. We identified multiple recombination events in our SAFV-1 strains, specifically recombination between SAFV-2, -3, -4, -9, -10 and the prototype SAFV-1 strain in the VP4 region and recombination between SAFV-4, -6, -8, -10, -11 and prototype SAFV-1 in the VP1/2A region. Notably, recombination in the structural gene VP4 is a rare event in Cardiovirus. The ratio of nonsynonymous substitutions to synonymous substitutions indicates a purifying selection of the SAFV genome. Phylogenetic and molecular clock analysis indicates the existence of at least two subclades of SAFV-1 with different origins. Subclade 1 includes two strains isolated from Pakistan, whereas subclade 2 includes the prototype strain and strains isolated in China, Pakistan, and Afghanistan. The most recent common ancestor of all SAFV genotypes dates to the 1710s, and SAFV-1, -2, and -3 to the 1940s, 1950s, and 1960s, respectively. No obvious relationship between variation and pathogenicity exists in the critical domains of the CD and EF loops of viral capsid proteins or the multi-functional proteins L based on amino acid sequence identity comparison between SAFV genotypes. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that intertypic recombination plays an important role in the diversity of SAFVs, highlighting the diversity of the five strains with the previously described SAFV-1 strains.

  16. Advantage of recombinant borrelial proteins for serodiagnosis of neuroborreliosis.

    Science.gov (United States)

    Kaiser, R; Rauer, S

    1999-01-01

    Two enzyme immunoassay (EIA) systems were compared for their ability to detect Borrelia burgdorferi sensu lato specific IgG and IgM antibodies and to differentiate between symptomatic (83 patients with neuroborreliosis) and asymptomatic seropositive subjects (80 healthy controls). Antibody concentrations were determined by EIA; the antigens used were either a sonicate of B. burgdorferi or three recombinant borrelial proteins: the 14-kDa flagellin fragment, the outer surface protein C (22 kDa) and the high molecular mass protein p83 (83 kDa). In the sonicate, EIA, IgG or IgM antibodies to B. burgdorferi, or both, were detected in all patients with neuroborreliosis and in all controls. Pre-absorption of sera with Treponema phagedenis sonicate diminished the sensitivity of detection of borrelial specific IgG (IgG or IgM or both) antibodies in patients with neuroborreliosis from 80 to 57% (100 to 82%) and in the controls from 100 to 32% (100 to 37%). While being specific for B. burgdorferi, the recombinant EIAs proved to be significantly more sensitive than the sonicate EIA: IgG or IgM, or both antibodies against any of the recombinant antigens were detected in 92% of patients with neuroborreliosis and in 24% of controls. The increase in sensitivity in patients with neuroborreliosis was mostly due to the higher detection rate of IgM antibodies in the recombinant EIA (77% versus 48% in the sonicate EIA), while IgG antibodies were demonstrated with similar frequencies in both EIA systems (57% versus 60%). It was concluded that the recombinant EIAs are superior to the sonicate EIA with pre-absorption of cross-reactive antibodies in the confirmation of an acute borrelial infection and in the differentiation between symptomatic and asymptomatic infections.

  17. Recombination in the human Pseudoautosomal region PAR1.

    Directory of Open Access Journals (Sweden)

    Anjali G Hinch

    2014-07-01

    Full Text Available The pseudoautosomal region (PAR is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this obligatory crossover occurs remains unknown, as does the fine-scale positioning of crossovers across this region. Recent research in mice has suggested that crossovers in PAR may be mediated independently of the protein PRDM9, which localises virtually all crossovers in the autosomes. To investigate recombination in this region, we construct the most fine-scale genetic map containing directly observed crossovers to date using African-American pedigrees. We leverage recombination rates inferred from the breakdown of linkage disequilibrium in human populations and investigate the signatures of DNA evolution due to recombination. Further, we identify direct PRDM9 binding sites using ChIP-seq in human cells. Using these independent lines of evidence, we show that, in contrast with mouse, PRDM9 does localise peaks of recombination in the human PAR1. We find that recombination is a far more rapid and intense driver of sequence evolution in PAR1 than it is on the autosomes. We also show that PAR1 hotspot activities differ significantly among human populations. Finally, we find evidence that PAR1 hotspot positions have changed between human and chimpanzee, with no evidence of sharing among the hottest hotspots. We anticipate that the genetic maps built and validated in this work will aid research on this vital and fascinating region of the genome.

  18. Constraints contributed by chromatin looping limit recombination targeting during Ig class switch recombination.

    Science.gov (United States)

    Feldman, Scott; Achour, Ikbel; Wuerffel, Robert; Kumar, Satyendra; Gerasimova, Tatiana; Sen, Ranjan; Kenter, Amy L

    2015-03-01

    Engagement of promoters with distal elements in long-range looping interactions has been implicated in regulation of Ig class switch recombination (CSR). The principles determining the spatial and regulatory relationships among Igh transcriptional elements remain poorly defined. We examined the chromosome conformation of C region (CH) loci that are targeted for CSR in a cytokine-dependent fashion in mature B lymphocytes. Germline transcription (GLT) of the γ1 and ε CH loci is controlled by two transcription factors, IL-4-inducible STAT6 and LPS-activated NF-κB. We showed that although STAT6 deficiency triggered loss of GLT, deletion of NF-κB p50 abolished both GLT and γ1 locus:enhancer looping. Thus, chromatin looping between CH loci and Igh enhancers is independent of GLT production and STAT6, whereas the establishment and maintenance of these chromatin contacts requires NF-κB p50. Comparative analysis of the endogenous γ1 locus and a knock-in heterologous promoter in mice identified the promoter per se as the interactive looping element and showed that transcription elongation is dispensable for promoter/enhancer interactions. Interposition of the LPS-responsive heterologous promoter between the LPS-inducible γ3 and γ2b loci altered GLT expression and essentially abolished direct IgG2b switching while maintaining a sequential μ→γ3→γ2b format. Our study provides evidence that promoter/enhancer looping interactions can introduce negative constraints on distal promoters and affect their ability to engage in germline transcription and determine CSR targeting.

  19. Constraints contributed by chromatin looping limit recombination targeting during Ig class switch recombination.

    Science.gov (United States)

    Feldman, Scott; Achour, Ikbel; Wuerffel, Robert; Kumar, Satyendra; Gerasimova, Tatiana; Sen, Ranjan; Kenter, Amy L

    2015-03-01

    Engagement of promoters with distal elements in long-range looping interactions has been implicated in regulation of Ig class switch recombination (CSR). The principles determining the spatial and regulatory relationships among Igh transcriptional elements remain poorly defined. We examined the chromosome conformation of C region (CH) loci that are targeted for CSR in a cytokine-dependent fashion in mature B lymphocytes. Germline transcription (GLT) of the γ1 and ε CH loci is controlled by two transcription factors, IL-4-inducible STAT6 and LPS-activated NF-κB. We showed that although STAT6 deficiency triggered loss of GLT, deletion of NF-κB p50 abolished both GLT and γ1 locus:enhancer looping. Thus, chromatin looping between CH loci and Igh enhancers is independent of GLT production and STAT6, whereas the establishment and maintenance of these chromatin contacts requires NF-κB p50. Comparative analysis of the endogenous γ1 locus and a knock-in heterologous promoter in mice identified the promoter per se as the interactive looping element and showed that transcription elongation is dispensable for promoter/enhancer interactions. Interposition of the LPS-responsive heterologous promoter between the LPS-inducible γ3 and γ2b loci altered GLT expression and essentially abolished direct IgG2b switching while maintaining a sequential μ→γ3→γ2b format. Our study provides evidence that promoter/enhancer looping interactions can introduce negative constraints on distal promoters and affect their ability to engage in germline transcription and determine CSR targeting. PMID:25624452

  20. RNA Recombination Enhances Adaptability and Is Required for Virus Spread and Virulence.

    Science.gov (United States)

    Xiao, Yinghong; Rouzine, Igor M; Bianco, Simone; Acevedo, Ashley; Goldstein, Elizabeth Faul; Farkov, Mikhail; Brodsky, Leonid; Andino, Raul

    2016-04-13

    Mutation and recombination are central processes driving microbial evolution. A high mutation rate fuels adaptation but also generates deleterious mutations. Recombination between two different genomes may resolve this paradox, alleviating effects of clonal interference and purging deleterious mutations. Here we demonstrate that recombination significantly accelerates adaptation and evolution during acute virus infection. We identified a poliovirus recombination determinant within the virus polymerase, mutation of which reduces recombination rates without altering replication fidelity. By generating a panel of variants with distinct mutation rates and recombination ability, we demonstrate that recombination is essential to enrich the population in beneficial mutations and purge it from deleterious mutations. The concerted activities of mutation and recombination are key to virus spread and virulence in infected animals. These findings inform a mathematical model to demonstrate that poliovirus adapts most rapidly at an optimal mutation rate determined by the trade-off between selection and accumulation of detrimental mutations. PMID:27078068

  1. uv induced enhancement of recombination among lambda bacteriophages: relation with replication of irradiated DNA

    Energy Technology Data Exchange (ETDEWEB)

    Cordone, L.; Sperandeo-Mineo, R.M.; Mannino, S.

    1975-07-01

    Experimental results are reported showing the dependence of the uv induced enhancement of recombinants on the presence of the functional O gene product. This fact is tentatively interpreted as a replication dependence of the uv induced recombination.

  2. Correlations between recombination rate and intron distributions along chromosomes of C.elegans

    Institute of Scientific and Technical Information of China (English)

    Hong Li; Guoqing Liu; Xuhua Xia

    2009-01-01

    Generally speaking,the intron size positively correlates with recombination rate in Caenorhabditis elegans genome.Here,we analyze the correlations between recombination rate and some measures of different intron lengths so as to know whether the recombination influences the introns of different lengths in the same way.Results show that the correlation between the recombination rate and the percentage of short introns(<100 bp)is negative,but the correlation between the recombination rate and the percentage of introns that are larger than 500 bp is positive.Average intron length correlates positively with the recombination rate for introns whose length is in the range of 100-1000 bp.We speculate that the recombination mainly exerts impact on introns whose length ranges from 100-1000 bp.We also show that the average intron number per gene correlates negatively with the recombination rate.

  3. Recombination Efficiency and Width in Bilayer Organic Light-emitting Devices

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A bilayer model with ohmic anode contact and injection limited cathode contact has been proposed to calculate the recombination efficiency and recombination zone width of the device. The effects of the thickness of hole transport layer and the barriers of organic/organic interface on the combination efficiency and recombination width have been discussed. It is found that: (1) When the electrons are blocked fully and the holes are not blocked significantly at the organic/organic interface, for a given Lh/L, the recombination efficiency increases with increasing the applied voltage, but at a higher applied voltage, the recombination efficiency decreases with increasing Lh/L; (2) The recombination efficiency increases with increasing applied voltage and H′h, and when applied voltage and H′h exceed some value, the recombination efficiency appears as a plateau; (3) The recombination width decreases with increasing the applied voltage and Lh/L. This model might explain the relative experiment phenomena.

  4. Initial recombination in the track of heavy charged particles: Numerical solution for air filled ionization chambers

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki;

    2012-01-01

    Introduction Modern particle therapy facilities enable sub-millimeter precision in dose deposition. Here, also ionization chambers (ICs) are used, which requires knowledge of the recombination effects. Up to now, recombination is corrected using phenomenological approaches for practical reasons. ...

  5. Genetic recombination in Escherichia coli : II. Calculation of incorporation frequency and relative map distance by recombinant analysis

    NARCIS (Netherlands)

    Haan, P.G. de; Verhoef, C.

    1966-01-01

    In this paper a mathematical analysis based on the physical exchange of genetic material is presented for a four-factor cross. The incorporation frequency of donor markers and the relative map distances may be accurately estimated from the frequencies of the eight recombinant classes. The results ob

  6. Chemical inactivation of recombinant vaccinia viruses and the effects on antigenicity and immunogenicity of recombinant simian immunodeficiency virus envelope glycoproteins.

    NARCIS (Netherlands)

    E.G.J. Hulskotte (Ellen); M.E.M. Dings (Marlinda); S.G. Norley (Stephen); A.D.M.E. Osterhaus (Albert)

    1997-01-01

    textabstractThe efficiency of paraformaldehyde (PFA) and binary ethylenimine (BEI) in inactivating recombinant vaccinia virus (rVV), present in baby hamster kidney cells expressing simian immunodeficiency virus envelope glycoproteins (SIV-Env), was measured in a series of inactivation studies. Both

  7. Similarity of recombinant human perlecan domain 1 by alternative expression systems bioactive heterogenous recombinant human perlecan D1

    DEFF Research Database (Denmark)

    Ellis, April L; Pan, Wensheng; Yang, Guang;

    2010-01-01

    BACKGROUND: Heparan sulfate glycosaminoglycans are diverse components of certain proteoglycans and are known to interact with growth factors as a co-receptor necessary to induce signalling and growth factor activity. In this report we characterize heterogeneously glycosylated recombinant human pe...

  8. Bounds on the minimum number of recombination events in a sample history.

    OpenAIRE

    Myers, Simon R; Griffiths, Robert C.

    2003-01-01

    Recombination is an important evolutionary factor in many organisms, including humans, and understanding its effects is an important task facing geneticists. Detecting past recombination events is thus important; this article introduces statistics that give a lower bound on the number of recombination events in the history of a sample, on the basis of the patterns of variation in the sample DNA. Such lower bounds are appropriate, since many recombination events in the history are typically un...

  9. Dimer-atom-atom recombination in the universal four-boson system

    OpenAIRE

    Deltuva, A

    2012-01-01

    The dimer-atom-atom recombination process in the system of four identical bosons with resonant interactions is studied. The description uses the exact Alt, Grassberger and Sandhas equations for the four-particle transition operators that are solved in the momentum-space framework. The dimer-dimer and atom-trimer channel contributions to the ultracold dimer-atom-atom recombination rate are calculated. The dimer-atom-atom recombination rate greatly exceeds the three-atom recombination rate.

  10. Sum rules for meson and baryon production in the quark recombination model

    International Nuclear Information System (INIS)

    A quark recombination model with quark distributions according to a generalized Kuti-Weisskopf model is used. Mesons are formed by v-s (valence-sea) and s-s recombination, baryons by vvv, vvs, vss and sss recombination. Sum rules for energy momentum concervation, baryon number, valence and sea quarks are shown to constrain the recombination parameters of the model significantly. The resulting model is consistent with experimental data. (author)

  11. Effects of Supplementation of Various Medium Components on Chinese Hamster Ovary Cell Cultures Producing Recombinant Antibody

    OpenAIRE

    Kim, Do Yun; Lee, Joon Chul; Chang, Ho Nam; Oh, Duk Jae

    2005-01-01

    Thirteen vitamins, twenty amino acids, hormones, inorganic salts, and other chemical agents, which constitute typical serum-free media, were evaluated for the development of fortified medium to enhance cell growth and productivity of recombinant antibody in the cultures of the recombinant Chinese hamster ovary (rCHO) cells. Two different rCHO cell lines, rCHO-A producing recombinant antibodies against the human platelet and rCHO-B secreting recombinant antibodies against the S surface antigen...

  12. Frequent Intra-Subtype Recombination among HIV-1 Circulating in Tanzania

    OpenAIRE

    Ireen E Kiwelu; Vladimir Novitsky; Lauren Margolin; Jeannie Baca; Rachel Manongi; Noel Sam; John Shao; McLane, Mary F.; Saidi H Kapiga; Essex, M

    2013-01-01

    The study estimated the prevalence of HIV-1 intra-subtype recombinant variants among female bar and hotel workers in Tanzania. While intra-subtype recombination occurs in HIV-1, it is generally underestimated. HIV-1 env gp120 V1-C5 quasispecies from 45 subjects were generated by single-genome amplification and sequencing (median (IQR) of 38 (28-50) sequences per subject). Recombination analysis was performed using seven methods implemented within the recombination detection program version 3,...

  13. Frequent Intra-Subtype Recombination among HIV-1 Circulating in Tanzania

    OpenAIRE

    Ireen E Kiwelu; Novitsky, Vladimir; Margolin, Lauren; Baca, Jeannie; Manongi, Rachel; Sam, Noel; Shao, John; McLane, Mary F.; Saidi H Kapiga; Essex, M

    2013-01-01

    The study estimated the prevalence of HIV-1 intra-subtype recombinant variants among female bar and hotel workers in Tanzania. While intra-subtype recombination occurs in HIV-1, it is generally underestimated. HIV-1 env gp120 V1-C5 quasispecies from 45 subjects were generated by single-genome amplification and sequencing (median (IQR) of 38 (28–50) sequences per subject). Recombination analysis was performed using seven methods implemented within the recombination detection program version 3,...

  14. Trends in the electric field enhancement of dielectronic recombination cross sections

    International Nuclear Information System (INIS)

    The effect of external electric fields on the dielectronic recombination cross section of selected ions has been studied in the configuration-average, distorted wave approximation. By applying the linear-Stark approximation to the doubly-excited Rydberg states formed from resonant recombination, we examine the systematics of field-mixing effects on dielectronic recombination and determine the maximum field enhancement of dielectronic recombination cross sections. 8 references, 6 figures, 3 tables

  15. Ad 2.0: a novel recombineering platform for high-throughput generation of tailored adenoviruses

    OpenAIRE

    Mück-Häusl, Martin; Solanki, Manish; Zhang, Wenli; Ruzsics, Zsolt; Ehrhardt, Anja

    2015-01-01

    Recombinant adenoviruses containing a double-stranded DNA genome of 26–45 kb were broadly explored in basic virology, for vaccination purposes, for treatment of tumors based on oncolytic virotherapy, or simply as a tool for efficient gene transfer. However, the majority of recombinant adenoviral vectors (AdVs) is based on a small fraction of adenovirus types and their genetic modification. Recombineering techniques provide powerful tools for arbitrary engineering of recombinant DNA. Here, we ...

  16. Fibroblast interleukin 1 beta: synergistic stimulation by recombinant interleukin 1 and tumor necrosis factor and posttranscriptional regulation.

    OpenAIRE

    Elias, J. A.; Reynolds, M M; Kotloff, R M; Kern, J A

    1989-01-01

    To understand the role fibroblasts play in mediating and amplifying the effects of inflammatory cytokines, we determined whether recombinant interleukin 1 (IL-1) and recombinant tumor necrosis factor (TNF), alone and in combination, stimulated fibroblasts to produce IL-1 beta. Recombinant IL-1 (alpha and beta) stimulated fibroblast IL-1 beta mRNA accumulation, whereas recombinant TNF did not. In addition, simultaneous stimulation with recombinant IL-1 (alpha or beta) and recombinant TNF resul...

  17. The significance of detection of D-dimer, fibrinogen and antithrombin-Ⅲin the patients with typy-2 diabet-ic nephropathy%D-二聚体、纤维蛋白原及抗凝血酶Ⅲ联合检测对早期2型糖尿病肾病的诊断价值

    Institute of Scientific and Technical Information of China (English)

    杨玲

    2015-01-01

    目的:探究D-二聚体、纤维蛋白原( FIB)及抗凝血酶Ⅲ( AT-Ⅲ)联合检测2型糖尿病早期肾损伤的临床诊断价值。方法选取某院2型糖尿病患者206例,根据24 h尿白蛋白排泄率( UAE)分为无蛋白尿组116例( UAE<30 mg/24 h)与微量白蛋白尿组90例(30 mg/24 h≤UAE<300 mg/24 h),并选取同期健康体检者103例作为健康对照组,比较血浆D-二聚体、FIB、AT-Ⅲ3项指标的变化。结果微量白蛋白尿组D-二聚体、FIB含量明显高于无蛋白尿组和健康对照组,差异均有统计学意义(P<0畅05),而三组AT-Ⅲ的活性比较差异无统计学意义(P>0畅05)。3项指标联合检测的微量蛋白尿组患者为93畅3%,比单项检测的阳性率高,差异有统计学意义(P<0畅05)。 D-二聚体、FIB、AT-Ⅲ与尿白蛋白排泄率呈正相关,相关系数(r)依次为0畅812、0畅672、0畅621(P<0畅05)。结论 D-二聚体、FIB检测对于2型糖尿病肾病的早期判断以及疾病的早期预防和病情监测有重要意义。%Objective To explore the D-dimer, fibrinogen (FIB), antithrombin Ⅲ (AT-Ⅲ) joint detection of early renal damage in type 2 diabetes to assess the diagnostic value of clinical application.Methods According to the 24 h urine albumin excre-tion rate ( UAE) , 206 patients selected from type 2 diabetes patients were divided into 116 cases without albuminuria group ( UAE0.05).Three indicators of joint detection of trace albuminuria group of patients was 93.3%, positive rate than single detection are high, the difference was statistically significant (P<0.05).D-dimer, FIB, the AT-Ⅲand UAE are positively related to the level of the correlation coefficient r of 0.812, 0.672, and 0.621 (P<0.05).Conclusion The detection of D-dimer, FIB in type 2 diabetic nephropathy early judgement and early prevention of disease and illness monitoring is im-portant.

  18. Clinical significance on changes of platelet aggregation test, von Willebrand factor,antithrombin and D-dimer assayin acute cerebral infarction patients%急性脑梗死患者血小板聚集功能、血管性血友病因子、抗凝血酶及 D-二聚体测定的临床意义

    Institute of Scientific and Technical Information of China (English)

    叶青跃; 程鹏飞; 周有利; 饶汉武; 黄承芳; 周立

    2015-01-01

    目的:探讨急性脑梗死患者血小板聚集功能( PAgT)、血管性血友病因子( vWF)、抗凝血酶( AT)和D-二聚体( D-dimer)水平变化及临床意义。方法选用相应的方法和仪器测定112例脑梗死及80例健康对照者血(浆) PAgT、vWF、AT和D-dimer水平变化,同时对部分患者进行治疗前、后的对比分析。结果脑梗死患者血中PAgT、vWF、D-dimer等指标均明显高于健康对照组,AT活性较对照组显著降低,差异有统计学意义(P<0.05或P<0.01)。选取经治疗效果明显好转的78例脑梗死患者,出院前取空腹静脉血测定PAgT、vWF、AT、D-dimer等指标,并与治疗前对照,结果治疗后PAgT、vWF、D-dimer降低,AT活性升高,差异有统计学意义(P<0.05或P<0.01)。结论脑梗死患者体内存在明显的凝血及纤溶功能异常,与血管内皮损伤、血小板聚集功能增强、凝血及纤溶功能亢进、抗凝功能降低等多因素有关。 PAgT、vWF、AT、D-dimer可以作为脑梗死患者诊断、治疗监测和预后判断的参考指标。%Objective To evaluate the clinical signification of coagulation ,anti-coagulation and fibrinolysis indexes i.e.platelet aggrega-tion test(PAgT),von Willebrand factor(vWF),antithrombin(AT),D-dimer in acute cerebral infarction patients.Methods vWF was as-sayed using ELISA method,AT was determined by chromogenic substances assay,and Latex enhanced immune turbidimetry for D-dimer. vWF,AT and D-dimer all the parameters were finished by SysmexCA-7000 automated blood coagulation analyzer.PAgT was measured sim-ultaneously using a whole-blood Lumi-Aggregometer by CHRMNO-LOG platelet aggregation apparatus.Results PAgT, vWF, D-dimer were significantly higher in acute cerebral infarction patients group,compared with those in the control group(P<0.05 or P<0.01). while AT was significantly lower(P<0.05).After effective treatment,PAgT,vWF,AT,D-dimer Indicators are all

  19. Expression of Recombinant Baculovirus Carrying Schistosoma japonicum 26 ku GST in Mammalian Cells

    Institute of Scientific and Technical Information of China (English)

    YU Guangqing; SONG Jianhua; LIU Wenqi; LONG Xiaochun; MO Hongmei; LI Yonglong; CHEN Xinwen

    2006-01-01

    In order to construct recombinant baculovirus carrying Schistosoma japonicum 26 ku glutathione S-transferase gene (Sj26), and observe the expression of Sj26 in mammalian cells, the Sj26 gene was amplified with plasmid pGEX-3X as template by PCR, and then recombined into Tvector for sequencing. Sj26 gene was inserted into the downstream of CMV promoter of donor plasmid pFBDGC, and the recombinant donor plasmid pFBDGC-Sj26 transformed into DH10Bac,then the recombinant bacmid AcCMVSj26 was isolated and transfected into Sf9 cells. The recombinant baculovirus was harvested and final titer of vAcCMVSj26 was measured. BHK cells were transducted with recombinant baculovirus in vitro. By using Western blot, the expression of 26 ku glutathione S-transferase (GST) was detected. The results showed that after enzyme digestion and sequencing, the donor plasmid was successfully constructed. PCR confirmed that pFBDGC-Sj26 and Bacmid homologous recombination occurred in E. coli. After transfection of Sf9 cells with recombinant Bacmid, recombinant baculovirus was replicated in Sf9 cells and expressed green fluorescent protein. PCR further revealed recombinant baculovirus contained Sj26. The titer of the harvested baculovirus was 1.24 × 108. Western blot demonstrated that recombinant baculovirus could express 26 ku GST in BHK cells. It was concluded that Sj26 recombinant baculovirus was successfully constructed, and the 26 ku GST was expressed in mammalian cells.

  20. Intracellular transport of recombinant coronavirus spike proteins: implications for virus assembly

    NARCIS (Netherlands)

    Horzinek, M.C.; Vennema, H.; Heijnen, L.; Zijderveld, A.; Spaan, W.J.M.

    1990-01-01

    Coronavirus spike protein genes were expressed in vitro by using the recombinant vaccinia virus expression system. Recombinant spike proteins were expressed at the cell surface and induced cell fusion in a host-cell-dependent fashion. The intracellular transport of recombinant spike proteins was stu

  1. Heterosis and recombination effects on pig reproductive traits.

    Science.gov (United States)

    Cassady, J P; Young, L D; Leymaster, K A

    2002-09-01

    The objective was to estimate breed, heterosis, and recombination effects on pig reproductive traits in two different four-breed composite populations. Breeds included Yorkshire, Landrace, Large White, and Chester White in Exp. 1 and Duroc, Hampshire, Pietrain, and Spot in Exp. 2. Data were recorded on purebred pigs, two-breed cross pigs, and pigs from generations F1 through F6, where F1 pigs were the first generation of a four-breed cross. Litter traits were considered a trait of the gilt. There were 868 first parity litters in Exp. 1 and 865 in Exp. 2. Direct heterosis significantly increased sow weight at 110 d of gestation and litter weight at 14 and 28 d (weaning) in both experiments. Direct heterosis significantly increased number of nipples, weight at puberty, lactation weight loss, litter size, and litter birth weight in Exp. 2. Gestation length in Exp. 1 and age at puberty in Exp. 1 and Exp. 2 were significantly decreased by direct heterosis. Maternal heterosis significantly increased age at puberty in Exp. 2 and decreased sow weight at 110 d of gestation in Exp. 1. Recombination significantly increased sow weight at 110 d of gestation and tended to increase total number born and litter birth weight in Exp. 1. Recombination significantly decreased age at puberty in Exp. 2. Litter heterosis significantly increased number of pigs at 14 and 28 d; litter weights at birth, 14, and 28 d; and tended to increase lactation weight loss in Exp. 1. Litter heterosis decreased litter size in Exp. 2. Maternal heterosis and recombination effects had a sampling correlation of -0.97 in Exp. 1 and -0.91 in Exp. 2 for number of fully formed pigs. Therefore, maternal heterosis and recombination effects were summed, and their net effect was tested. This net effect tended to increase number of nipples, lactation weight loss, and litter birth weight and significantly increased number of fully formed pigs in Exp. 1. Direct, maternal, and litter heterosis and recombination effects

  2. DNA helicases in recombination and repair: construction of a delta uvrD delta helD delta recQ mutant deficient in recombination and repair.

    OpenAIRE

    Mendonca, V M; Klepin, H D; Matson, S W

    1995-01-01

    DNA helicases play pivotal roles in homologous recombination and recombinational DNA repair. They are involved in both the generation of recombinogenic single-stranded DNA ends and branch migration of synapsed Holliday junctions. Escherichia coli helicases II (uvrD), IV (helD), and RecQ (recQ) have all been implicated in the presynaptic stage of recombination in the RecF pathway. To probe for functional redundancy among these helicases, mutant strains containing single, double, and triple del...

  3. The role of recombination in the emergence of a complex and dynamic HIV epidemic

    Directory of Open Access Journals (Sweden)

    Morgenstern Burkhard

    2010-03-01

    Full Text Available Abstract Background Inter-subtype recombinants dominate the HIV epidemics in three geographical regions. To better understand the role of HIV recombinants in shaping the current HIV epidemic, we here present the results of a large-scale subtyping analysis of 9435 HIV-1 sequences that involve subtypes A, B, C, G, F and the epidemiologically important recombinants derived from three continents. Results The circulating recombinant form CRF02_AG, common in West Central Africa, appears to result from recombination events that occurred early in the divergence between subtypes A and G, followed by additional recent recombination events that contribute to the breakpoint pattern defining the current recombinant lineage. This finding also corrects a recent claim that G is a recombinant and a descendant of CRF02, which was suggested to be a pure subtype. The BC and BF recombinants in China and South America, respectively, are derived from recent recombination between contemporary parental lineages. Shared breakpoints in South America BF recombinants indicate that the HIV-1 epidemics in Argentina and Brazil are not independent. Therefore, the contemporary HIV-1 epidemic has recombinant lineages of both ancient and more recent origins. Conclusions Taken together, we show that these recombinant lineages, which are highly prevalent in the current HIV epidemic, are a mixture of ancient and recent recombination. The HIV pandemic is moving towards having increasing complexity and higher prevalence of recombinant forms, sometimes existing as "families" of related forms. We find that the classification of some CRF designations need to be revised as a consequence of (1 an estimated > 5% error in the original subtype assignments deposited in the Los Alamos sequence database; (2 an increasing number of CRFs are defined while they do not readily fit into groupings for molecular epidemiology and vaccine design; and (3 a dynamic HIV epidemic context.

  4. Steady-state photoluminescent excitation characterization of semiconductor carrier recombination

    Science.gov (United States)

    Bhosale, J. S.; Moore, J. E.; Wang, X.; Bermel, P.; Lundstrom, M. S.

    2016-01-01

    Photoluminescence excitation spectroscopy is a contactless characterization technique that can provide valuable information about the surface and bulk recombination parameters of a semiconductor device, distinct from other sorts of photoluminescent measurements. For this technique, a temperature-tuned light emitting diode (LED) has several advantages over other light sources. The large radiation density offered by LEDs from near-infrared to ultraviolet region at a low cost enables efficient and fast photoluminescence measurements. A simple and inexpensive LED-based setup facilitates measurement of surface recombination velocity and bulk Shockley-Read-Hall lifetime, which are key parameters to assess device performance. Under the right conditions, this technique can also provide a contactless way to measure the external quantum efficiency of a solar cell.

  5. Effective conductance method for the primordial recombination spectrum

    CERN Document Server

    Ali-Haïmoud, Yacine

    2012-01-01

    As atoms formed for the first time during primordial recombination, they emitted bound-bound and free-bound radiation leading to spectral distortions to the cosmic microwave background. These distortions might become observable in the future with high-sensitivity spectrometers, and provide a new window into physical conditions in the early universe. The standard multilevel atom method habitually used to compute the recombination spectrum is computationally expensive, impeding a detailed quantitative exploration of the information contained in spectral distortions thus far. In this work it is shown that the emissivity in optically thin allowed transitions can be factored into a computationally expensive but cosmology-independent part and a computationally cheap, cosmology-dependent part. The slow part of the computation consists in pre-computing temperature-dependent effective "conductances", linearly relating line or continuum intensity to departures from Saha equilibrium of the lowest-order excited states (2...

  6. Proton to pion ratio at RHIC from dynamical quark recombination

    CERN Document Server

    Ayala, Alejandro; Paic, Guy; Toledo-Sanchez, Genaro

    2008-01-01

    We propose an scenario to study, from a dynamical point of view, the thermal recombination of quarks in the midsts of a relativistic heavy-ion collision. We coin the term dynamical quark recombination to refer to the process of quark-antiquark and three-quark clustering, to form mesons and baryons, respectively, as a function of energy density. Using the string-flip model we show that the probabilities to form such clusters differ. We apply these ideas to the calculation of the proton and pion spectra in a Bjorken-like scenario that incorporates the evolution of these probabilities with proper time and compute the proton to pion ratio, comparing to recent RHIC data at the highest energy. We show that for a standard choice of parameters, this ratio reaches one, though the maximum is very sensitive to the initial evolution proper time.

  7. Characterization of recombinant Raccoonpox Vaccine Vectors in Chickens

    Science.gov (United States)

    Hwa, S.-H.; Iams, K.P.; Hall, J.S.; Kingstad, B.A.; Osorio, J.E.

    2010-01-01

    Raccoonpox virus (RCN) has been used as a recombinant vector against several mammalian pathogens but has not been tested in birds. The replication of RCN in chick embryo fibroblasts (CEFs) and chickens was studied with the use of highly pathogenic avian influenza virus H5N1 hemagglutinin (HA) as a model antigen and luciferase (luc) as a reporter gene. Although RCN replicated to low levels in CEFs, it efficiently expressed recombinant proteins and, in vivo, elicited anti-HA immunoglobulin yolk (IgY) antibody responses comparable to inactivated influenza virus. Biophotonic in vivo imaging of 1-wk-old chicks with RCN-luc showed strong expression of the luc reporter gene lasting up to 3 days postinfection. These studies demonstrate the potential of RCN as a vaccine vector for avian influenza and other poultry pathogens. ?? American Association of Avian Pathologists 2010.

  8. Recombinant cells that highly express chromosomally-integrated heterologous gene

    Science.gov (United States)

    Ingram, Lonnie O.; Ohta, Kazuyoshi; Wood, Brent E.

    2007-03-20

    Recombinant host cells are obtained that comprise (A) a heterologous, polypeptide-encoding polynucleotide segment, stably integrated into a chromosome, which is under transcriptional control of an endogenous promoter and (B) a mutation that effects increased expression of the heterologous segment, resulting in enhanced production by the host cells of each polypeptide encoded by that segment, relative to production of each polypeptide by the host cells in the absence of the mutation. The increased expression thus achieved is retained in the absence of conditions that select for cells displaying such increased expression. When the integrated segment comprises, for example, ethanol-production genes from an efficient ethanol producer like Zymomonas mobilis, recombinant Escherichia coli and other enteric bacterial cells within the present invention are capable of converting a wide range of biomass-derived sugars efficiently to ethanol.

  9. IDENTIFICATION OF PATHOGENIC LEPTOSPIRES BY RECOMBINANT DNA PROBES

    Institute of Scientific and Technical Information of China (English)

    戴保民; 肖建国; 沈成义

    1994-01-01

    Early diagnosis of leptospirosis of pulmonary diffuse bernorrhage type (PDH) is of crucial importance in saving patients. To develop a sensitive and specific method for diagnvsis, a genonlic library of the main pathogen of PDH, L. interogans serovar lai strath 017, was constructed with the plasmid vector pUC9. Recmbinant plasmids which have hornologotLq fragments of pathogenic inptospires were screened from the bank. A recombinant plasmid.designated pCX7, could detect 1. 7 kb fragment of strain 017. 9. 0 kb of strain 601 and 30. 0 kb of strain Hebdo-maclis, respectively, without cross hybridization with nonpathogcnic leptospires such as L. biflexa strain Patoc 1 and Leptonema illini. The recombinant plasmid pCX7 could detect pathogenic leptospires which are the main pathogens endemic to Sichuan Province.

  10. Intragenic recombination in the CSR1 locus of Arabidopsis.

    Science.gov (United States)

    Mourad, G; Haughn, G; King, J

    1994-04-01

    Four classes of herbicides are known to inhibit plant acetolactate synthase (ALS). In Arabidopsis, ALS is encoded by a single gene, CSR1. The dominant csr1-1 allele encodes an ALS resistant to chlorsulfuron and triazolopyrimidine sulfonamide while the dominant csr1-2 allele encodes an ALS resistant to imazapyr and pyrimidyl-oxy-benzoate. The molecular distance between the point mutations in csr1-1 and csr1-2 is 1369 bp. Here we used multiherbicide resistance as a stringent selection to measure the intragenic recombination frequency between these two point mutations. We found this frequency to be 0.008 +/- 0.0028. The recombinant multiherbicide-resistant allele, csr1-4, provides an ideal marker for plant genetic transformation. PMID:8177214

  11. Transgenic Expression of the Recombinant Phytase in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    LIU Qiao-quan; LI Qian-feng; JIANG Li; ZHANG Da-jiang; WANG Hong-mei; GU Ming-hong; YAO Quan-hong

    2006-01-01

    In most of the cereal crop, phytic acid is the main storage form of phosphorus, which can decrease the bioavailability of phosphate. Transgenic expression of phytase is regarded as an efficient way to release phosphate from phytate in transgenic plants.In this study, a plant expression vector, containing the recombinant phytase gene driven by the maize ubiquitin (Ubi) promoter was constructed and introduced into an elite rice variety via Agrobacterium-mediated transformation. During the experiment, a total of 15 independent transgenic rice lines were regenerated. The results of PCR and Southern blot indicated that the target gene was integrated into the genome of transgenic rice plants. Moreover, the RT-PCR analysis of total RNAs extracted from the immature seeds of several transgenic lines showed that the recombinant phytase gene could be normally expressed. The inorganic phosphorus content, both in the mature seeds and the leaf was significantly higher in the transgenic plants than in the untransformed wild type.

  12. Dissociative recombination in reactive flows related to planetary atmospheric entries

    Directory of Open Access Journals (Sweden)

    Bultel Arnaud

    2015-01-01

    Full Text Available The Dissociative Recombination (DR processes play a significant role in plasma chemistry. This article illustrates this role from the modeling point of view in the case of reactive flows related to atmospheric entry plasmas. Two situations are investigated, for which the studied plasma is nitrogen. The first configuration corresponds to the relaxation process behind a strong shock wave moving at high Mach number in a shock tube, the second one to the recombination taking place in an expanding plasma flowing in a diverging nozzle. In both cases, the collisional-radiative model CoRaM-N2, involving N2, N, N2+, N+ and electrons, is implemented in an Eulerian 1D code able to compute the aerodynamic fields; calculations are performed in standard conditions. We show that, according to the rate coefficients used for the DR processes, the population density of the charged species especially N2+ is strongly modified only for the post-shock flow.

  13. Transfer line from the PSB to the PS (recombination)

    CERN Multimedia

    1976-01-01

    After sequential ejection of 5 bunches from each of the 4 rings of the Booster (originally 800 MeV, now 1.4 GeV), the 4 batches are brought to the same vertical level, so as to form a string of 20 bunches, filling the circumference of the PS. This vertical "recombination" is performed in the transfer line, using vertical bending magnets, septa and kickers. Here we see the section where the beam from ring 4 (the top one) is brought down to the level of ring 3, and the beam from ring 1 up to the level of ring 2. Further downstream (to the right, outside this picture), level 2 is brought up to level 3, identical to that of the PS. After this original recombination scheme, other ways of combining the 4 beams, vertically and/or longitudinally, were developed and used in operation.

  14. Antigenic structures stably expressed by recombinant TGEV-derived vectors.

    Science.gov (United States)

    Becares, Martina; Sanchez, Carlos M; Sola, Isabel; Enjuanes, Luis; Zuñiga, Sonia

    2014-09-01

    Coronaviruses (CoVs) are positive-stranded RNA viruses with potential as immunization vectors, expressing high levels of heterologous genes and eliciting both secretory and systemic immune responses. Nevertheless, its high recombination rate may result in the loss of the full-length foreign gene, limiting their use as vectors. Transmissible gastroenteritis virus (TGEV) was engineered to express porcine reproductive and respiratory syndrome virus (PRRSV) small protein domains, as a strategy to improve heterologous gene stability. After serial passage in tissue cultures, stable expression of small PRRSV protein antigenic domains was achieved. Therefore, size reduction of the heterologous genes inserted in CoV-derived vectors led to the stable expression of antigenic domains. Immunization of piglets with these TGEV vectors led to partial protection against a challenge with a virulent PRRSV strain, as immunized animals showed reduced clinical signs and lung damage. Further improvement of TGEV-derived vectors will require the engineering of vectors with decreased recombination rate.

  15. Insulin allergy treated with human insulin (recombinant DNA).

    Science.gov (United States)

    De Leeuw, I; Delvigne, C; Bekaert, J

    1982-01-01

    Two insulin-dependent diabetic subjects treated with pork and beef insulin during a period of 6 mo developed severe local reactions. Both patients had an important allergic history (asthma, urticaria, drug reactions, rhinitis). Skin-testing revealed type I allergy to beef and pork insulin. Specific IgE-insulin binding was demonstrated with both insulins. After negative skin testing with NPH Lilly human insulin (recombinant DNA), treatment was started with this compound and remained successful during a period of 6-9 mo. In one patient a local reaction occurred when regular human insulin (recombinant DNA) was added to NPH in order to obtain better control. Skin testing with regular human insulin was positive, but not with NPH human insulin alone. The mechanism of this phenomenon remains unsolved. PMID:6765530

  16. Steady-state photoluminescent excitation characterization of semiconductor carrier recombination

    Energy Technology Data Exchange (ETDEWEB)

    Bhosale, J. S. [Intel Corporation, Hillsboro, Oregon 97124 (United States); Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Moore, J. E.; Wang, X.; Bermel, P.; Lundstrom, M. S. [Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2016-01-15

    Photoluminescence excitation spectroscopy is a contactless characterization technique that can provide valuable information about the surface and bulk recombination parameters of a semiconductor device, distinct from other sorts of photoluminescent measurements. For this technique, a temperature-tuned light emitting diode (LED) has several advantages over other light sources. The large radiation density offered by LEDs from near-infrared to ultraviolet region at a low cost enables efficient and fast photoluminescence measurements. A simple and inexpensive LED-based setup facilitates measurement of surface recombination velocity and bulk Shockley-Read-Hall lifetime, which are key parameters to assess device performance. Under the right conditions, this technique can also provide a contactless way to measure the external quantum efficiency of a solar cell.

  17. Production of Recombinant Chemokines and Validation of Refolding.

    Science.gov (United States)

    Veldkamp, Christopher T; Koplinski, Chad A; Jensen, Davin R; Peterson, Francis C; Smits, Kaitlin M; Smith, Brittney L; Johnson, Scott K; Lettieri, Christina; Buchholz, Wallace G; Solheim, Joyce C; Volkman, Brian F

    2016-01-01

    The diverse roles of chemokines in normal immune function and many human diseases have motivated numerous investigations into the structure and function of this family of proteins. Recombinant chemokines are often used to study how chemokines coordinate the trafficking of immune cells in various biological contexts. A reliable source of biologically active protein is vital for any in vitro or in vivo functional analysis. In this chapter, we describe a general method for the production of recombinant chemokines and robust techniques for efficient refolding that ensure consistently high biological activity. Considerations for initiating development of protocols consistent with Current Good Manufacturing Practices (cGMPs) to produce biologically active chemokines suitable for use in clinical trials are also discussed. PMID:26921961

  18. Steady-state photoluminescent excitation characterization of semiconductor carrier recombination

    International Nuclear Information System (INIS)

    Photoluminescence excitation spectroscopy is a contactless characterization technique that can provide valuable information about the surface and bulk recombination parameters of a semiconductor device, distinct from other sorts of photoluminescent measurements. For this technique, a temperature-tuned light emitting diode (LED) has several advantages over other light sources. The large radiation density offered by LEDs from near-infrared to ultraviolet region at a low cost enables efficient and fast photoluminescence measurements. A simple and inexpensive LED-based setup facilitates measurement of surface recombination velocity and bulk Shockley-Read-Hall lifetime, which are key parameters to assess device performance. Under the right conditions, this technique can also provide a contactless way to measure the external quantum efficiency of a solar cell

  19. Fragmentation Functions for Heavy Baryons in the Recombination Model

    Institute of Scientific and Technical Information of China (English)

    彭茹

    2011-01-01

    Using the shower parton distributions determined by the recombination model, we predict the fragmentation functions for heavy baryons. Then we obtain the completed fragmentation functions of heavy quarks (c and b) splitting into their hadrons (mesons and baryons containing one heavy valence quark). The calculated process shows that the fragmentation functions for mesons and baryons are not independent if the hadronization of the shower partons is taken into account.%Using the shower parton distributions determined by the recombination model,we predict the fragmentation functions for heavy baryons.Then we obtain the completed fragmentation functions of heavy quarks(c and b)splitting into their hadrons(mesons and baryons containing one heavy valence quark).The calculated process shows that the fragmentation functions for mesons and baryons are not independent if the hadronization of the shower partons is taken into account.

  20. A new recombinant factor VIII: from genetics to clinical use.

    Science.gov (United States)

    Santagostino, Elena

    2014-01-01

    Advances in recombinant technology and knowledge about coagulation factor VIII (FVIII) are building a platform for new therapeutic options in patients with hemophilia A. The development of turoctocog alfa, a novel, high-purity, third-generation, B-domain truncated recombinant FVIII, has been produced and formulated without the use of animal-derived or human serum-derived components, in the wake of understanding of the new biochemical characteristics of FVIII, namely its protein structure, and glycosylation and sulfating patterns. Culture conditions and a five-step purification process have been developed to optimize the safety of turoctocog alfa. The results of two pilot clinical trials using turoctocog alfa confirmed high safety levels, with no patient developing inhibitors during the period of observation. The purpose of this review is to describe briefly the molecular and biological properties of turoctocog alfa, together with details of its clinical development, with emphasis on the needs of patients with hemophilia A. PMID:25548513

  1. Commercialisation of a recombinant vaccine against Boophilus microplus.

    Science.gov (United States)

    Willadsen, P; Bird, P; Cobon, G S; Hungerford, J

    1995-01-01

    Increasingly, there is need for methods to control cattle tick (Boophilus microplus) infestations by the use of non-chemical technology. This need is brought about by a mixture of market forces and the failure or inadequacy of existing technology. A recombinant vaccine has now been developed against the tick. This vaccine relies on the uptake with the blood meal of antibody directed against a critical protein in the tick gut. The isolation of the vaccine antigen, Bm86, and its production as a recombinant protein is briefly described. The vaccine has been tested in the field, has been taken through the full registration process and is now in commercial use in Australia. A related development has occurred in Cuba. The potential for improvement of the current vaccine and for the development of similar vaccines against other haematophagous parasites is discussed. PMID:7784128

  2. Recombinant protein production from stable mammalian cell lines and pools.

    Science.gov (United States)

    Hacker, David L; Balasubramanian, Sowmya

    2016-06-01

    We highlight recent developments for the production of recombinant proteins from suspension-adapted mammalian cell lines. We discuss the generation of stable cell lines using transposons and lentivirus vectors (non-targeted transgene integration) and site-specific recombinases (targeted transgene integration). Each of these methods results in the generation of cell lines with protein yields that are generally superior to those achievable through classical plasmid transfection that depends on the integration of the transfected DNA by non-homologous DNA end-joining. This is the main reason why these techniques can also be used for the generation of stable cell pools, heterogenous populations of recombinant cells generated by gene delivery and genetic selection without resorting to single cell cloning. This allows the time line from gene transfer to protein production to be reduced.

  3. Use of Recombinant Antigens for the Diagnosis of Invasive Candidiasis

    Directory of Open Access Journals (Sweden)

    Ana Laín

    2008-01-01

    Full Text Available Invasive candidiasis is a frequent and often fatal complication in immunocompromised and critically ill patients. Unfortunately, the diagnosis of invasive candidiasis remains difficult due to the lack of specific clinical symptoms and a definitive diagnostic method. The detection of antibodies against different Candida antigens may help in the diagnosis. However, the methods traditionally used for the detection of antibodies have been based on crude antigenic fungal extracts, which usually show low-reproducibility and cross-reactivity problems. The development of molecular biology techniques has allowed the production of recombinant antigens which may help to solve these problems. In this review we will discuss the usefulness of recombinant antigens in the diagnosis of invasive candidiasis.

  4. Electron-ion recombination study in argon at atmospheric pressure

    International Nuclear Information System (INIS)

    This study deals with a wall-stabilized arc burning in argon at atmospheric pressure. A transient mode is obtained using a fast thyristor connected to the electrodes, which short-circuits the discharge. By means of two wavelengths laser interferometry and spectroscopy measurements we have determined the temporal changes of the electron density, ground state atom density and excited atom density. We have shown that, when the electric field is suppressed, the electron temperature rapidly decreases to the gas temperature before changing electron and atom densities. This phenomenon is applied to determine the gas temperature and to evaluate the role played by ionization in electron density balance. The coefficients of ambipolar diffusion, ionization and recombination and an apparent recombination coefficient are determined versus electron temperature and compared with theoretical values

  5. Construction of recombinant DNA clone for bovine viral diarrhea virus

    International Nuclear Information System (INIS)

    Molecular cloning was carried out on the Danish strain of bovine viral diarrhea virus (BVDV) to construct strategy for the diagnostic tools and effective vaccine of BVD afterwards. A recombinant DNA clone (No. 29) was established successfully from cDNA for viral RNA tailed with adenine homopolymer at 3 -end. 32P-labeled DNA probes of 300~1, 800bp fragments, originating from the clone 29, directed specific DNA-RNA hybridization results with BVDV RNA. Recombinant DNA of the clone 29 was about 5,200bp representing 41.6% of the full length of Danish strain's RNA, and restriction sites were recognized for EooR I, Sst I, Hind III and Pst I restriction enzymes in the DNA fragment

  6. In-tank hydrogen-ferric ion recombination

    Science.gov (United States)

    Selverston, S.; Savinell, R. F.; Wainright, J. S.

    2016-08-01

    An H2sbnd Fe3+ recombination method is being developed for all-iron flow batteries. Working principles are described and a proof-of-concept in-tank reactor is demonstrated. A membrane-less galvanic reactor is characterized using potential, polarization and impedance measurements at hydrogen partial pressures ranging from 0.3 to 11.3 psig. Through a vertical reactor geometry, hydrogen recombination rates of up to 60 mA cm-2 were measured at PH2 = 4.5 psig for a reactor with a platinum loading of 3.2 mg cm-2, based on the geometric catalyzed area. This is equivalent to over 375 mA cm-2 with respect to the cross sectional area of the reactor at the waterline. This rate is sufficient that the reactor will readily fit inside the positive reservoir of a flow battery. The reactor was found to be resistant to degradation by flooding or catalyst loss.

  7. Construction and expression of recombined human AFP eukaryotic expression vector

    Institute of Scientific and Technical Information of China (English)

    Li-Wang Zhang; Yang-Lin Pan; Stephen M Festein; Jun Ren; Liang Zhang; Hong-Mei Zhang; Bin Jin; Bo-Rong Pan; Xiao-Ming Si; Yan-Jun Zhang; Zhong-Hua Wang

    2003-01-01

    AIM: To construct a recombined human AFP eukaryotic expression vector for the purpose of gene therapy and target therapy of hepatocellular carcinoma (HCC).METHODS: The full length AFP-cDNA of prokaryotic vector was digested, and subcloned to the multi-clony sites of the eukaryotic vector. The constructed vector was confirmed by enzymes digestion and electrophoresis, and the product expressed was detected by electrochemiluminescence and immunofluorescence methods.RESULTS: The full length AFP-cDNA successfully cloned to the eukaryotic vector through electrophoresis, 0.9723 IU/ml AFP antigen was detected in the supernatant of AFPCHO by electrochemiluminescence method. Compared with the control groups, the differences were significant (P<0.05).AFP antigen molecule was observed in the plasma of AFPCHO by immunofluorescence staining.CONCLUSION: The recombined human AFP eukaryotic expression vector can express in CHO cell line. It provides experimental data for gene therapy and target therapy of hepatocellular carcinoma.

  8. Improved and simplified recombineering approach for influenza virus reverse genetics

    OpenAIRE

    Liu, Qinfang; Wang, Shuai; Ma, Guangpeng; Pu, Juan; Forbes, Nicole E.; Brown, Earl G.; Liu, Jin-Hua

    2009-01-01

    Typical reverse genetics systems for generating influenza viruses require the insertion of each genome segments by DNA ligation into vectors for genome synthesis and expression. Herein is described the construction and use of a novel pair of plasmid vectors for cloning all eight genome segments of influenza A virus by homologous recombination for influenza virus reverse genetics. Plasmids, pLLBA and pLLBG, were constructed to possess opposing RNA polymerase I and RNA polymerase II transcripti...

  9. Plasmid transfer and genetic recombination by protoplast fusion in staphylococci.

    OpenAIRE

    Götz, F; Ahrné, S.; Lindberg, M

    1981-01-01

    The experimental conditions for plasmid transfer and genetic recombination in Staphylococcus aureus and some coagulase-negative staphylococci by protoplast fusion are described. Protoplasts were prepared by treatment with lysostaphin and lysozyme in a buffered medium with 0.7 to 0.8 M sucrose. Regeneration of cell walls was accomplished on a hypertonic agar medium containing succinate and bovine serum albumin. Transfer of plasmids occurred after treatment of the protoplast mixtures with polye...

  10. Recombinant pharmaceuticals from microbial cells: a 2015 update

    OpenAIRE

    Sanchez-Garcia, Laura; Martín, Lucas; Mangues, Ramon; Ferrer-Miralles, Neus; Vázquez, Esther; Villaverde, Antonio

    2016-01-01

    Diabetes, growth or clotting disorders are among the spectrum of human diseases related to protein absence or malfunction. Since these pathologies cannot be yet regularly treated by gene therapy, the administration of functional proteins produced ex vivo is required. As both protein extraction from natural producers and chemical synthesis undergo inherent constraints that limit regular large-scale production, recombinant DNA technologies have rapidly become a choice for therapeutic protein pr...

  11. Experimental investigation of ion–ion recombination under atmospheric conditions

    OpenAIRE

    A. Franchin; S. Ehrhart; Leppä, J.; Nieminen, T.; Gagné, S.; Schobesberger, S.; D. Wimmer; J. Duplissy; Riccobono, F.; E. M. Dunne; L. Rondo; Downard, A.; BIANCHI, F.; Kupc, A.; Tsagkogeorgas, G.

    2015-01-01

    We present the results of laboratory measurements of the ion–ion recombination coefficient at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at CERN, the walls of which are made of conductive material, making it possible to measure small ions. We produced ions in the chamber using a 3.5 GeV c−1 beam of positively charged pions (π+) gener...

  12. Expression, purification, and immobilization of recombinant tamavidin 2 fusion proteins.

    Science.gov (United States)

    Takakura, Yoshimitsu; Oka, Naomi; Tsunashima, Masako

    2014-01-01

    Tamavidin 2 is a fungal avidin-like protein that binds biotin with high affinity. Unlike avidin or streptavidin, tamavidin 2 in soluble form is produced at high levels in Escherichia coli. In this chapter, we describe a method for immobilization and purification of recombinant proteins with the use of tamavidin 2 as an affinity tag. The protein fused to tamavidin 2 is tightly immobilized and simultaneously purified on biotinylated magnetic microbeads without loss of activity. PMID:24943317

  13. Taxing the rich: recombinations and bubble growth during reionization

    Science.gov (United States)

    Furlanetto, Steven R.; Oh, S. Peng

    2005-11-01

    Reionization is inhomogeneous for two reasons: the clumpiness of the intergalactic medium (IGM), and clustering of the discrete ionizing sources. While numerical simulations can in principle take both into account, they are at present limited by small box sizes. On the other hand, analytic models have only examined the limiting cases of a clumpy IGM (with uniform ionizing emissivity) and clustered sources (embedded in a uniform IGM). Here, we present the first analytic model that includes both factors. At first, recombinations can be ignored and ionized bubbles grow primarily through major mergers, because at any given moment the bubbles have a well-defined characteristic size. As a result, reionization resembles `punctuated equilibrium,' with a series of well-separated sharp jumps in the ionizing background. These features are local effects and do not reflect similar jumps in the global ionized fraction. We then combine our bubble model with a simple description of recombinations in the IGM. We show that the bubbles grow until recombinations balance ionizations, when their expansion abruptly halts. If the IGM density structure is similar to that at moderate redshifts, this limits the bubble radii to ~20 comoving Mpc; however, if the IGM is significantly clumpier at higher redshifts (because of minihalo formation, for example), the limit could be much smaller. Once a bubble reaches saturation, that region of the Universe has for all intents and purposes entered the `post-overlap' stage. Because different HII regions saturate over a finite time interval, the overlap epoch actually has a finite width. Our model also predicts a mean recombination rate several times larger than expected for a uniformly illuminated IGM. This picture naturally explains the substantial large-scale variation in Lyman-series opacity along the lines of sight to the known z > 6 quasars. More quasar spectra will shed light on the transition between the `bubble-dominated' topology

  14. Human recombinant erythropoietin promotes differentiation of murine megakaryocytes in vitro.

    OpenAIRE

    Ishibashi, T.; Koziol, J A; Burstein, S A

    1987-01-01

    To determine if erythropoietin affects megakaryocytopoiesis, we measured acetylcholinesterase (AchE) activity, a marker of the murine megakaryocytic lineage, after the addition of human recombinant erythropoietin to serumless murine bone marrow cultures. Erythropoietin increased AchE activity substantially. Moreover, when the hormone was added to serumless cultures of 426 isolated single megakaryocytes derived from megakaryocytic colonies, erythropoietin induced a significant increase in the ...

  15. Mathematical modeling of recombinant Escherichia coli aerobic batch fermentations

    OpenAIRE

    Costa, Rafael S; Rocha, I; Ferreira, E. C.

    2008-01-01

    In this work, three competing unstructured mathematical models for the biomass growth by recombinant E. coli strains with different acetate inhibition kinetics terms were evaluated for batch processes at constant temperature and pH. The models considered the dynamics of biomass growth, acetate accumulation, substrate consumption, Green Fluorescence Protein (GFP) production and three metabolic pathways for E. coli. Parameter estimation and model validation was carried out usi...

  16. Intraclonal Protein Expression Heterogeneity in Recombinant CHO Cells

    OpenAIRE

    Pilbrough, Warren; Munro, Trent P.; Gray, Peter

    2009-01-01

    Therapeutic glycoproteins have played a major role in the commercial success of biotechnology in the post-genomic era. But isolating recombinant mammalian cell lines for large-scale production remains costly and time-consuming, due to substantial variation and unpredictable stability of expression amongst transfected cells, requiring extensive clone screening to identify suitable high producers. Streamlining this process is of considerable interest to industry yet the underlying phenomena are...

  17. Thrombocytopenic purpura as adverse reaction to recombinant hepatitis B vaccine

    OpenAIRE

    Ronchi, F; Cecchi, P; Falcioni, F.; Marsciani, A; Minak, G.; Muratori, G; Tazzari, P; Beverini, S

    1998-01-01

    Three cases of immune thrombocytopenic purpura after the first dose of recombinant hepatitis B vaccine occurred in infants under 6 months of age. Other possible causes of this condition were excluded. Antiplatelet antibodies were present. A defect in platelet production was excluded in two children. Corticosteroid treatment was effective. Subsequent administration of other vaccines (against polio, diphtheria, and tetanus) did not cause relapse of thrombocytopenia.



  18. Effectiveness of Recombinant Human Growth Hormone for Pharyngocutaneous Fistula Closure

    OpenAIRE

    Kucuk, Nurten; Sari, Murat; Midi, Ahmet; Yumusakhuylu, Ali Cemal; Findik, Ozan; Binnetoglu, Adem

    2015-01-01

    Objectives In laryngeal cancer, which comprises 25% of head and neck cancer, chemotherapy has come into prominence with the increase in organ-protective treatments. With such treatment, salvage surgery has increased following recurrence; the incidence of pharyngocutaneous fistula has also increased in both respiratory and digestive system surgery. We investigated the effects of recombinant human growth hormone on pharyngocutaneous fistula closure in Sprague-Dawley rats, based on an increase i...

  19. Studies of recombinant forms of Aleuria aurantia lectin

    OpenAIRE

    Olausson, Johan

    2009-01-01

    The presented work describes construction and analysis of recombinantly produced forms of Aleuria aurantia lectin (AAL). The binding properties of the produced AAL forms were studied using techniques such as tryptophan fluorescence, hemagglutination analysis, ELISA and surface plasmon resonance analysis. Lectins are proteins that are ubiquitous in nature with the ability to bind specifically to different types of carbohydrates. The physiological function of different lectins is not always kno...

  20. An improved method of xylose utilization by recombinant Saccharomyces cerevisiae.

    Science.gov (United States)

    Ma, Tien-Yang; Lin, Ting-Hsiang; Hsu, Teng-Chieh; Huang, Chiung-Fang; Guo, Gia-Luen; Hwang, Wen-Song

    2012-10-01

    The aim of this study was to develop a method to optimize expression levels of xylose-metabolizing enzymes to improve xylose utilization capacity of Saccharomyces cerevisiae. A xylose-utilizing recombinant S. cerevisiae strain YY2KL, able to express nicotinamide adenine dinucleotide phosphate, reduced (NADPH)-dependent xylose reductase (XR), nicotinamide adenine dinucleotide (NAD(+))-dependent xylitol dehydrogenase (XDH), and xylulokinase (XK), showed a low ethanol yield and sugar consumption rate. To optimize xylose utilization by YY2KL, a recombinant expression plasmid containing the XR gene was transformed and integrated into the aur1 site of YY2KL. Two recombinant expression plasmids containing an nicotinamide adenine dinucleotide phosphate (NADP(+))-dependent XDH mutant and XK genes were dually transformed and integrated into the 5S ribosomal DNA (rDNA) sites of YY2KL. This procedure allowed systematic construction of an S. cerevisiae library with different ratios of genes for xylose-metabolizing enzymes, and well-grown colonies with different xylose fermentation capacities could be further selected in yeast protein extract (YPX) medium (1 % yeast extract, 2 % peptone, and 2 % xylose). We successfully isolated a recombinant strain with a superior xylose fermentation capacity and designated it as strain YY5A. The xylose consumption rate for strain YY5A was estimated to be 2.32 g/gDCW/h (g xylose/g dry cell weight/h), which was 2.34 times higher than that for the parent strain YY2KL (0.99 g/gDCW/h). The ethanol yield was also enhanced 1.83 times by this novel method. Optimal ratio and expression levels of xylose-metabolizing enzymes are important for efficient conversion of xylose to ethanol. This study provides a novel method that allows rapid and effective selection of ratio-optimized xylose-utilizing yeast strains. This method may be applicable to other multienzyme systems in yeast.