Unreduced gamete formation in wheat × Aegilops spp. hybrids is genotype specific and prevented by shared homologous subgenomes.

PubMed

Fakhri, Zhaleh; Mirzaghaderi, Ghader; Ahmadian, Samira; Mason, Annaliese S

2016-05-01

The presence of homologous subgenomes inhibited unreduced gamete formation in wheat × Aegilops interspecific hybrids. Unreduced gamete rates were under the control of the wheat nuclear genome. Production of unreduced gametes is common among interspecific hybrids, and may be affected by parental genotypes and genomic similarity. In the present study, five cultivars of Triticum aestivum and two tetraploid Aegilops species (i.e. Ae. triuncialis and Ae. cylindrica) were reciprocally crossed to produce 20 interspecific hybrid combinations. These hybrids comprised two different types: T. aestivum × Aegilops triuncialis; 2n = ABDU(t)C(t) (which lack a common subgenome) and T. aestivum × Ae. cylindrica; 2n = ABDD(c)C(c) (which share a common subgenome). The frequency of unreduced gametes in F1 hybrids was estimated in sporads from the frequency of dyads, and the frequency of viable pollen, germinated pollen and seed set were recorded. Different meiotic abnormalities recorded in the hybrids included precocious chromosome migration to the poles at metaphase I and II, laggards in anaphase I and II, micronuclei and chromosome stickiness, failure in cell wall formation, premature cytokinesis and microspore fusion. The mean frequency of restitution meiosis was 10.1 %, and the mean frequency of unreduced viable pollen was 4.84 % in T. aestivum × Ae. triuncialis hybrids. By contrast, in T. aestivum × Ae. cylindrica hybrids no meiotic restitution was observed, and a low rate of viable gametes (0.3 %) was recorded. This study present evidence that high levels of homologous pairing between the D and D(c) subgenomes may interfere with meiotic restitution and the formation of unreduced gametes. Variation in unreduced gamete production was also observed between T. aestivum × Ae. triuncialis hybrid plants, suggesting genetic control of this trait.

Globalization and gametes: reproductive 'tourism,' Islamic bioethics, and Middle Eastern modernity.

PubMed

Inhorn, Marcia C

2011-04-01

'Reproductive tourism' has been defined as the search for assisted reproductive technologies (ARTs) and human gametes (eggs, sperm, embryos) across national and international borders. This article conceptualizes reproductive tourism within 'global reproscapes,' which involve the circulation of actors, technologies, money, media, ideas, and human gametes, all moving in complicated manners across geographical landscapes. Focusing on the Muslim countries of the Middle East, the article explores the Islamic 'local moral worlds' informing the movements of Middle Eastern infertile couples. The ban on third-party gamete donation in Sunni Muslim-majority countries and the recent allowance of donor technologies in the Shia Muslim-majority countries of Iran and Lebanon have led to significant movements of infertile couples across Middle Eastern national borders. In the new millennium, Iran is leading the way into this 'brave new world' of high-tech, third-party assisted conception, with Islamic bioethical discourses being used to justify various forms of technological assistance. Although the Middle East is rarely regarded in this way, it is a key site for understanding the intersection of technoscience, religious morality, and modernity, all of which are deeply implicated in the new world of reproductive tourism.

PI(4,5)P2 regulates myoblast fusion through Arp2/3 regulator localization at the fusion site

PubMed Central

Bothe, Ingo; Deng, Su; Baylies, Mary

2014-01-01

Cell-cell fusion is a regulated process that requires merging of the opposing membranes and underlying cytoskeletons. However, the integration between membrane and cytoskeleton signaling during fusion is not known. Using Drosophila, we demonstrate that the membrane phosphoinositide PI(4,5)P2 is a crucial regulator of F-actin dynamics during myoblast fusion. PI(4,5)P2 is locally enriched and colocalizes spatially and temporally with the F-actin focus that defines the fusion site. PI(4,5)P2 enrichment depends on receptor engagement but is upstream or parallel to actin remodeling. Regulators of actin branching via Arp2/3 colocalize with PI(4,5)P2 in vivo and bind PI(4,5)P2 in vitro. Manipulation of PI(4,5)P2 availability leads to impaired fusion, with a reduction in the F-actin focus size and altered focus morphology. Mechanistically, the changes in the actin focus are due to a failure in the enrichment of actin regulators at the fusion site. Moreover, improper localization of these regulators hinders expansion of the fusion interface. Thus, PI(4,5)P2 enrichment at the fusion site encodes spatial and temporal information that regulates fusion progression through the localization of activators of actin polymerization. PMID:24821989

Cell fusion and nuclear fusion in plants.

PubMed

Maruyama, Daisuke; Ohtsu, Mina; Higashiyama, Tetsuya

2016-12-01

Eukaryotic cells are surrounded by a plasma membrane and have a large nucleus containing the genomic DNA, which is enclosed by a nuclear envelope consisting of the outer and inner nuclear membranes. Although these membranes maintain the identity of cells, they sometimes fuse to each other, such as to produce a zygote during sexual reproduction or to give rise to other characteristically polyploid tissues. Recent studies have demonstrated that the mechanisms of plasma membrane or nuclear membrane fusion in plants are shared to some extent with those of yeasts and animals, despite the unique features of plant cells including thick cell walls and intercellular connections. Here, we summarize the key factors in the fusion of these membranes during plant reproduction, and also focus on "non-gametic cell fusion," which was thought to be rare in plant tissue, in which each cell is separated by a cell wall. Copyright © 2016 Elsevier Ltd. All rights reserved.

Artificial gametes, the unnatural and the artefactual.

PubMed

Smajdor, Anna; Cutas, Daniela; Takala, Tuija

2018-06-01

In debates on the ethics of artificial gametes, concepts of naturalness have been used in a number of different ways. Some have argued that the unnaturalness of artificial gametes means that it is unacceptable to use them in fertility treatments. Others have suggested that artificial gametes are no less natural than many other tissues or processes in common medical use. We suggest that establishing the naturalness or unnaturalness of artificial gametes is unlikely to provide easy answers as to the acceptability of using them in fertility medicine. However, we also suggest that we should be cautious about repudiating any relationship between nature and moral evaluation. The property of being natural or man-made may not per se tell us anything about an entity's moral status, but it has an important impact on the moral relationship between the creator and the created organism. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Sexual fusion and life history of Scytosiphon lomentaria (Scytosiphonaceae, Phaeophyceae) in Dalian, china

NASA Astrophysics Data System (ADS)

Li, Xiaoli; Zhang, Zeyu; Dong, Shuanglin; Cao, Shuqing

2011-06-01

Morphology and life history of a brown alga Scytosiphon lomentaria (Lyngbye) Link (Scytosiphonaceae, Phaeophyceae) were investigated from 2005 to 2009 in the coastal waters of Dalian, China. The erect thalli collected in the field were tubular, hollow, and commonly constricted at intervals. Ascocysts were presented. Plurilocular gametangia, which were positioned in continuous sori on the erect thallus surface, produced biflagellar gametes. Gametophytes were dioecious and gametes were nearly isogamous. Gametes fusion occurred in three types. Type one, female and male gametes fused directly while swimming; type two, female gamete settled first, with which a male one contacted and fused rapidly; type three, while settling adjacently, a male gamete's entire protoplast moved slowly into the previously settled female one, with only an empty cell membrane left. In culture zygotes developed into crustose sporophytes that formed unilocular sporangia. Biflagellar zoospores developed into erect thalli that formed plurilocular gametangia. The results indicated that a periodical heteromorphic alternation history with haploid gametophyte generation and diploid sporophyte generation exists in S. lomentaria of the Dalian populations.

Chapter 1 Historical Background on Gamete and Embryo Cryopreservation.

PubMed

Ali, Jaffar; AlHarbi, Naif H; Ali, Nafisa

2017-01-01

This chapter describes the development of the science of cryopreservation of gametes and embryos of various species including human. It attempts to record in brief the main contributions of workers in their attempts to cryopreserve gametes and embryos. The initial difficulties faced and subsequent developments and triumphs leading to present-day state of the art are given in a concise manner. The main players and their contributions are mentioned and the authors' aim is to do justice to them. This work also attempts to ensure that credit is correctly attributed for significant advances in gamete and embryo cryopreservation. In general this chapter has tried to describe the historical development of the science of cryopreservation of gametes and embryos as accurately as possible without bias or partiality.

Negotiating boundaries: Accessing donor gametes in India.

PubMed

Widge, A; Cleland, J

2011-01-01

This paper documents how couples and providers access donor materials for conception in the Indian context and perceptions about using them. The objective is to facilitate understanding of critical issues and relevant concerns. A postal survey was conducted with a sample of 6000 gynaecologists and in-depth interviews were -conducted with 39 gynaecologists in four cities. Donor gametes are relatively more acceptable than a few years ago, especially if confidentiality can be -maintained, though lack of availability of donor materials is sometimes an impediment to infertility treatment. Donor sperms are usually accessed from in-house or commercial sperm banks, pathology laboratories, IVF centres, -professional donors, relatives or friends. There is scepticism about screening procedures of sperm banks. Donor eggs are usually accessed from voluntary donors, friends, relatives, egg sharing programmes, donation from other patients, advertising and commercial donors. There are several concerns regarding informed consent for using donated gametes, using -relatives and friends gametes, the unregulated use of gametes and embryos, record keeping and documentation, -unethical and corrupt practices and commercialisation. These issues need to be addressed by patients, providers and regulatory authorities by providing -information, counselling, ensuring informed consent, addressing exploitation and commercialisation, ensuring -monitoring, proper documentation and transparency.

Negotiating boundaries: Accessing donor gametes in India

PubMed Central

Widge, A.; Cleland, J.

2011-01-01

Background: This paper documents how couples and providers access donor materials for conception in the Indian context and perceptions about using them. The objective is to facilitate understanding of critical issues and relevant concerns. Methods: A postal survey was conducted with a sample of 6000 gynaecologists and in-depth interviews were conducted with 39 gynaecologists in four cities. Results: Donor gametes are relatively more acceptable than a few years ago, especially if confidentiality can be maintained, though lack of availability of donor materials is sometimes an impediment to infertility treatment. Donor sperms are usually accessed from in-house or commercial sperm banks, pathology laboratories, IVF centres, professional donors, relatives or friends. There is scepticism about screening procedures of sperm banks. Donor eggs are usually accessed from voluntary donors, friends, relatives, egg sharing programmes, donation from other patients, advertising and commercial donors. There are several concerns regarding informed consent for using donated gametes, using relatives and friends gametes, the unregulated use of gametes and embryos, record keeping and documentation, unethical and corrupt practices and commercialisation. Conclusion: These issues need to be addressed by patients, providers and regulatory authorities by providing information, counselling, ensuring informed consent, addressing exploitation and commercialisation, ensuring monitoring, proper documentation and transparency. PMID:24753849

9 CFR 93.904 - Health certificate for live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., fertilized eggs, and gametes. 93.904 Section 93.904 Animals and Animal Products ANIMAL AND PLANT HEALTH... eggs, and gametes. (a) General. All live fish, fertilized eggs, and gametes of SVC-susceptible species... from the date of issuance. The health certificate for the live fish, fertilized eggs, or gametes must...

Exploitation of induced 2n-gametes for plant breeding.

PubMed

Younis, Adnan; Hwang, Yoon-Jung; Lim, Ki-Byung

2014-02-01

Unreduced gamete formation derived via abnormal meiotic cell division is an important approach to polyploidy breeding. This process is considered the main driving force in spontaneous polyploids formation in nature, but the potential application of these gametes to plant breeding has not been fully exploited. An effective mechanism for their artificial induction is needed to attain greater genetic variation and enable efficient use of unreduced gametes in breeding programs. Different approaches have been employed for 2n-pollen production including interspecific hybridization, manipulation of environmental factors and treatment with nitrous oxide, trifluralin, colchicine, oryzalin and other chemicals. These chemicals can act as a stimulus to produce viable 2n pollen; however, their exact mode of action, optimum concentration and developmental stages are still not known. Identification of efficient methods of inducing 2n-gamete formation will help increase pollen germination of sterile interspecific hybrids for inter-genomic recombination and introgression breeding to develop new polyploid cultivars and increase heterozygosity among plant populations. Additionally, the application of genomic tools and identification and isolation of genes and mechanisms involved in the induction of 2n-gamete will enable increased exploitation in different plant species, which will open new avenues for plant breeding.

Obtaining the variance of gametic diversity with genomic models

USDA-ARS?s Scientific Manuscript database

It may be possible to use information about the variability among gametes (spermatozoa and ova) to select parents that are more likely than average to produce offspring with extremely high or low breeding values. In this study, statistical formulae were developed to calculate variability among gamet...

Discovery of long-distance gamete dispersal in a lichen-forming ascomycete.

PubMed

Ronnås, Cecilia; Werth, Silke; Ovaskainen, Otso; Várkonyi, Gergely; Scheidegger, Christoph; Snäll, Tord

2017-10-01

Accurate estimates of gamete and offspring dispersal range are required for the understanding and prediction of spatial population dynamics and species persistence. Little is known about gamete dispersal in fungi, especially in lichen-forming ascomycetes. Here, we estimate the dispersal functions of clonal propagules, gametes and ascospores of the epiphytic lichen Lobaria pulmonaria. We use hierarchical Bayesian parentage analysis, which integrates genetic and ecological information from multiannual colonization and dispersal source data collected in a large, old-growth forest landscape. The effective dispersal range of gametes is several hundred metres to kilometres from potential paternal individuals. By contrast, clonal propagules disperse only tens of metres, and ascospores disperse over several thousand metres. Our study reveals the dispersal distances of individual reproductive units; clonal propagules, gametes and ascospores, which is of great importance for a thorough understanding of the spatial dynamics of ascomycetes. Sexual reproduction occurs between distant individuals. However, whereas gametes and ascospores disperse over long distances, the overall rate of colonization of trees is low. Hence, establishment is the limiting factor for the colonization of new host trees by the lichen in old-growth landscapes. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Multisource data fusion for documenting archaeological sites

NASA Astrophysics Data System (ADS)

Knyaz, Vladimir; Chibunichev, Alexander; Zhuravlev, Denis

2017-10-01

The quality of archaeological sites documenting is of great importance for cultural heritage preserving and investigating. The progress in developing new techniques and systems for data acquisition and processing creates an excellent basis for achieving a new quality of archaeological sites documenting and visualization. archaeological data has some specific features which have to be taken into account when acquiring, processing and managing. First of all, it is a needed to gather as full as possible information about findings providing no loss of information and no damage to artifacts. Remote sensing technologies are the most adequate and powerful means which satisfy this requirement. An approach to archaeological data acquiring and fusion based on remote sensing is proposed. It combines a set of photogrammetric techniques for obtaining geometrical and visual information at different scales and detailing and a pipeline for archaeological data documenting, structuring, fusion, and analysis. The proposed approach is applied for documenting of Bosporus archaeological expedition of Russian State Historical Museum.

Control of female gamete formation by a small RNA pathway in Arabidopsis.

PubMed

Olmedo-Monfil, Vianey; Durán-Figueroa, Noé; Arteaga-Vázquez, Mario; Demesa-Arévalo, Edgar; Autran, Daphné; Grimanelli, Daniel; Slotkin, R Keith; Martienssen, Robert A; Vielle-Calzada, Jean-Philippe

2010-03-25

In the ovules of most sexual flowering plants female gametogenesis is initiated from a single surviving gametic cell, the functional megaspore, formed after meiosis of the somatically derived megaspore mother cell (MMC). Because some mutants and certain sexual species exhibit more than one MMC, and many others are able to form gametes without meiosis (by apomixis), it has been suggested that somatic cells in the ovule are competent to respond to a local signal likely to have an important function in determination. Here we show that the Arabidopsis protein ARGONAUTE 9 (AGO9) controls female gamete formation by restricting the specification of gametophyte precursors in a dosage-dependent, non-cell-autonomous manner. Mutations in AGO9 lead to the differentiation of multiple gametic cells that are able to initiate gametogenesis. The AGO9 protein is not expressed in the gamete lineage; instead, it is expressed in cytoplasmic foci of somatic companion cells. Mutations in SUPPRESSOR OF GENE SILENCING 3 and RNA-DEPENDENT RNA POLYMERASE 6 exhibit an identical defect to ago9 mutants, indicating that the movement of small RNA (sRNAs) silencing out of somatic companion cells is necessary for controlling the specification of gametic cells. AGO9 preferentially interacts with 24-nucleotide sRNAs derived from transposable elements (TEs), and its activity is necessary to silence TEs in female gametes and their accessory cells. Our results show that AGO9-dependent sRNA silencing is crucial to specify cell fate in the Arabidopsis ovule, and that epigenetic reprogramming in companion cells is necessary for sRNA-dependent silencing in plant gametes.

9 CFR 93.905 - Declaration and other documents for live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2010 CFR

2010-01-01

... live fish, fertilized eggs, and gametes. 93.905 Section 93.905 Animals and Animal Products ANIMAL AND... for live fish, fertilized eggs, and gametes. (a) For all live fish, fertilized eggs, and gametes... fish, fertilized eggs, or gametes, the number, species, and the purpose of the importation, the name of...

9 CFR 93.905 - Declaration and other documents for live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2011 CFR

2011-01-01

... live fish, fertilized eggs, and gametes. 93.905 Section 93.905 Animals and Animal Products ANIMAL AND... for live fish, fertilized eggs, and gametes. (a) For all live fish, fertilized eggs, and gametes... fish, fertilized eggs, or gametes, the number, species, and the purpose of the importation, the name of...

9 CFR 93.903 - Import permits for live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., fertilized eggs, and gametes. 93.903 Section 93.903 Animals and Animal Products ANIMAL AND PLANT HEALTH... General Provisions for Svc-Regulated Fish Species § 93.903 Import permits for live fish, fertilized eggs, and gametes. (a) Live fish, fertilized eggs, or gametes of SVC-susceptible species imported into the...

9 CFR 93.903 - Import permits for live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., fertilized eggs, and gametes. 93.903 Section 93.903 Animals and Animal Products ANIMAL AND PLANT HEALTH... General Provisions for Svc-Regulated Fish Species § 93.903 Import permits for live fish, fertilized eggs, and gametes. (a) Live fish, fertilized eggs, or gametes of SVC-susceptible species imported into the...

Salmonid Gamete Preservation in the Snake River Basin, Annual Report 2002.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, William; Kucera, Paul

2003-07-01

In spite of an intensive management effort, chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss) populations in the Northwest have not recovered and are currently listed as threatened species under the Endangered Species Act. In addition to the loss of diversity from stocks that have already gone extinct, decreased genetic diversity resulting from genetic drift and inbreeding is a major concern. Reduced population and genetic variability diminishes the environmental adaptability of individual species and entire ecological communities. The Nez Perce Tribe (NPT), in cooperation with Washington State University and the University of Idaho, established a germplasm repository in 1992 inmore » order to preserve the remaining salmonid diversity in the region. The germplasm repository provides long-term storage for cryopreserved gametes. Although only male gametes can be cryopreserved, conserving the male component of genetic diversity will maintain future management options for species recovery. NPT efforts have focused on preserving salmon and steelhead gametes from the major river subbasins in the Snake River basin. However, the repository is available for all management agencies to contribute gamete samples from other regions and species. In 2002 a total of 570 viable semen samples were added to the germplasm repository. This included the gametes of 287 chinook salmon from the Lostine River, Catherine Creek, upper Grande Ronde River, Imnaha River (Lookingglass Hatchery), Lake Creek, South Fork Salmon River, Johnson Creek, Big Creek, Capehorn Creek, Marsh Creek, Pahsimeroi River (Pahsimeroi Hatchery), and upper Salmon River (Sawtooth Hatchery) and the gametes of 280 steelhead from the North Fork Clearwater River (Dworshak Hatchery), Fish Creek, Little Sheep Creek, Pahsimeroi River (Pahsimeroi Hatchery) and Snake River (Oxbow Hatchery). In addition, gametes from 60 Yakima River spring chinook and 34 Wenatchee River coho salmon were added to the

Vaginal gamete intrafallopian transfer. Experience with 14 cases.

PubMed

Lucena, E; Paulson, J D; Ruiz, J; Asmar, P; Mendoza, J C; Ortiz, J A; Gomez, M; Arango, A; Lucena, C; Lucena, A

1990-06-01

A procedure utilizing transvaginal aspiration of stimulated gametes followed by transcervical, ultrasound-guided catheterization of the tubal ostia was performed as a modification of the standardized gamete intrafallopian transfer (GIFT) technique. Among 14 patients with 16 cycles there were four normal, intrauterine pregnancies and one ectopic pregnancy. In two patients the beta-human gonadotropin level rose significantly and then started to fall; the patients aborted spontaneously. The procedure can be performed with a higher degree of patient acceptance than can traditional GIFT, and the success rate in this small series was promising.

The impact of disclosure on donor gamete participants: donors, intended parents and offspring.

PubMed

Greenfeld, Dorothy A

2008-06-01

The present review examines recent publications that provide insight into how the trend toward nonanonymity and disclosure in gamete donation impacts donors, intended parents, and their donor-conceived children. Recent findings show an increase in donor programs that offer open-identity between donors and offspring. The psychological needs of gamete donors and their attitudes toward disclosure are increasingly given consideration. Qualitative research on how parents of donor gamete offspring make decisions about disclosure reveals that even when couples initially disagree about disclosing to offspring, most ultimately come to a united disclosure decision. The literature on the impact of disclosure on donor gamete offspring has extended to include children conceived through embryo donation and children born as a result of surrogacy. The absence of genetic or gestational link between parents and their child does not have a negative impact on parent-child relationships. Parents through surrogacy tend to disclose the method of family creation to their child, whereas parents through embryo donation tend to be secretive about their child's origins. The trend toward greater openness in gamete donation has been accompanied by an increase in programs offering open-identity donation. In addition, the psychological needs of gamete donors and their attitudes toward disclosure are increasingly being given consideration. Parents of donor gamete offspring give careful thought to their disclosure decisions, and the psychological well being of donor-conceived children does not seem to be impacted by those decisions.

Segregation for Sexual Seed Production in Paspalum as Directed by Male Gametes of Apomictic Triploid Plants

PubMed Central

Martínez, Eric J.; Acuña, Carlos A.; Hojsgaard, Diego H.; Tcach, Mauricio A.; Quarin, Camilo L.

2007-01-01

Background and Aims Gametophytic apomixis is regularly associated with polyploidy. It has been hypothesized that apomixis is not present in diploid plants because of a pleiotropic lethal effect associated with monoploid gametes. Rare apomictic triploid plants for Paspalum notatum and P. simplex, which usually have sexual diploid and apomictic tetraploid races, were acquired. These triploids normally produce male gametes through meiosis with a range of chromosome numbers from monoploid (n = 10) to diploid (n = 20). The patterns of apomixis transmission in Paspalum were investigated in relation to the ploidy levels of gametes. Methods Intraspecific crosses were made between sexual diploid, triploid and tetraploid plants as female parents and apomictic triploid plants as male parents. Apomictic progeny were identified by using molecular markers completely linked to apomixis and the analysis of mature embryo sacs. The chromosome number of the male gamete was inferred from chromosome counts of each progeny. Key Results The chromosome numbers of the progeny indicated that the chromosome input of male gametes depended on the chromosome number of the female gamete. The apomictic trait was not transmitted through monoploid gametes, at least when the progeny was diploid. Diploid or near-diploid gametes transmitted apomixis at very low rates. Conclusions Since male monoploid gametes usually failed to form polyploid progenies, for example triploids after 4x × 3x crosses, it was not possible to determine whether apomixis could segregate in polyploid progenies by means of monoploid gametes. PMID:17766843

Evidence for participation of GCS1 in fertilization of the starlet sea anemone Nematostella vectensis: Implication of a common mechanism of sperm–egg fusion in plants and animals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebchuqin, Eerdundagula; Yokota, Naoto; Yamada, Lixy

Highlights: • GCS1 is a sperm transmembrane protein that is essential for gamete fusion in flowering plants. • The GCS1 gene is present not only in angiosperms but also in unicellular organisms and animals. • NvGCS1 gene is expressed in the testis and GCS1 protein exists in sperm of a sea anemone. • Anti-GCS1 antibodies inhibited the fertilization, showing the participation in fertilization. - Abstract: It has been reported that GCS1 (Generative Cell Specific 1) is a transmembrane protein that is exclusively expressed in sperm cells and is essential for gamete fusion in flowering plants. The GCS1 gene is presentmore » not only in angiosperms but also in unicellular organisms and animals, implying the occurrence of a common or ancestral mechanism of GCS1-mediated gamete fusion. In order to elucidate the common mechanism, we investigated the role of GCS1 in animal fertilization using a sea anemone (Cnidaria), Nematostella vectensis. Although the existence of the GCS1 gene in N. vectensis has been reported, the expression of GCS1 in sperm and the role of GCS1 in fertilization are not known. In this study, we showed that the GCS1 gene is expressed in the testis and that GCS1 protein exists in sperm by in situ hybridization and proteomic analysis, respectively. Then we made four peptide antibodies against the N-terminal extracellular region of NvGCS1. These antibodies specifically reacted to NvGCS1 among sperm proteins on the basis of Western analysis and potently inhibited fertilization in a concentration-dependent manner. These results indicate that sperm GCS1 plays a pivotal role in fertilization, most probably in sperm–egg fusion, in a starlet sea anemone, suggesting a common gamete-fusion mechanism shared by eukaryotic organisms.« less

Early and late HIV-1 membrane fusion events are impaired by sphinganine lipidated peptides that target the fusion site.

PubMed

Klug, Yoel A; Ashkenazi, Avraham; Viard, Mathias; Porat, Ziv; Blumenthal, Robert; Shai, Yechiel

2014-07-15

Lipid-conjugated peptides have advanced the understanding of membrane protein functions and the roles of lipids in the membrane milieu. These lipopeptides modulate various biological systems such as viral fusion. A single function has been suggested for the lipid, binding to the membrane and thus elevating the local concentration of the peptide at the target site. In the present paper, we challenged this argument by exploring in-depth the antiviral mechanism of lipopeptides, which comprise sphinganine, the lipid backbone of DHSM (dihydrosphingomyelin), and an HIV-1 envelope-derived peptide. Surprisingly, we discovered a partnership between the lipid and the peptide that impaired early membrane fusion events by reducing CD4 receptor lateral diffusion and HIV-1 fusion peptide-mediated lipid mixing. Moreover, only the joint function of sphinganine and its conjugate peptide disrupted HIV-1 fusion protein assembly and folding at the later fusion steps. Via imaging techniques we revealed for the first time the direct localization of these lipopeptides to the virus-cell and cell-cell contact sites. Overall, the findings of the present study may suggest lipid-protein interactions in various biological systems and may help uncover a role for elevated DHSM in HIV-1 and its target cell membranes.

Gamete competence assessment by polarizing optics in assisted reproduction.

PubMed

Montag, Markus; Köster, Maria; van der Ven, Katrin; van der Ven, Hans

2011-01-01

The purpose of this study was first to give an overview of the historical development of polarization microscopy, second to describe the various applications of this technique in assisted reproduction techniques (ART) and third to discuss the potential benefit of polarization microscopy as a predictor for IVF success. The history of polarization microscopy was undertaken by performing a backward search in the scientific literature using Google and internet sites of several Societies for Microscopy and Cell Biology. Studies of polarization microscopy in ART were identified by using a systematic literature search in PubMed and Scopus. A total of 62 articles were identified by the direct search and further relevant articles were found by screening the cited literature in these articles. The topics relevant for assisted reproduction were spindle and zona imaging in combination with IVF success, meiotic cell cycle progression, pharmaceutical studies and cryopreservation. A separate topic was the use of sperm birefringence in ART. The majority of studies are observational studies and were not performed in a randomized manner and there is no direct comparison of techniques using other gamete selection markers. Despite this, most studies show that polarization microscopy may help us to further increase our knowledge on gametes and meiosis. Whether certain applications such as spindle or zona imaging may lead to an increase in IVF success is unclear at present. Publications on the use of polarization microscopy on sperm are still very limited.

Effects of an oil production effluent on gametogenesis and gamete performance in the purple sea urchin (Strongylocentrotus purpuratus Stimpson)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krause, P.R.

1994-07-01

Adult organisms subjected to chronic discharges from a point source of pollution may exhibit several sublethal responses. One such response is the impairment of gamete production. This may be expressed in the amount and/or quality of gametes produced by adults. In this study the effects of chronic exposure to produced water (an oil production effluent) on the gametogenesis and gamete performance of the purple sea urchin (Strongylocentrotus purpuratus Stimpson) were examined using an in situ caging experiment. Adult purple sea urchins were kept in benthic cages arrayed down-field from a discharging diffuser at 13 sites, with distances ranging from 5more » to 1,000 m. Cage exposures were maintained in the field for eight weeks, and each cage held 25 animals. Gametogenesis was examined for each sex by comparing a size-independent measure of relative gonads ass as determined by analysis of covariance. Results showed that there was a significant negative relationship between these estimates of relative gonad mass and distance from the outfall for both sexes, indicating that sea urchins living closer to the outfall produced significantly larger gonads. Gamete performance was measured through a fertilization kinetics bioassay that held the concentration of eggs constant and varied the amount of sperm added. The proportion of eggs fertilized under each sperm concentration was determined and the response fit to a model of fertilizability showed a positive relationship with distance away from the outfall. These findings indicate that although adult sea urchins exposed to a produced water outfall exhibit larger gonads, they suffer a marked decrease in a gamete performance.« less

Potential consequences of clinical application of artificial gametes: a systematic review of stakeholder views.

PubMed

Hendriks, Saskia; Dondorp, Wybo; de Wert, Guido; Hamer, Geert; Repping, Sjoerd; Dancet, Eline A F

2015-01-01

Recent progress in the formation of artificial gametes, i.e. gametes generated from progenitors or somatic cells, has led to scientific and societal discussion about their use in medically assisted reproduction. In animals, live births have already been achieved using artificial gametes of varying (cell type) sources and biological research seems to be progressing steadily toward clinical application in humans. Artificial gametes could potentially help not only infertile heterosexual couples of reproductive age of which one or both partners lacks functional gametes, but also post-menopausal women and same-sex couples, to conceive a child who will be genetically related to them. But as clinical application of these new technologies may have wider societal consequences, a proactive consideration of the possible impact seems timely and important. This review aims to contribute to this by providing a systematic overview of the potential consequences of clinical application of artificial gametes anticipated by different stakeholders. The electronic database 'Medline/Pubmed' was systematically searched with medical subject heading terms (MesH) for articles published in English between January 1970 and December 2013. Articles were selected based on eligibility and reference lists of eligible studies were hand searched. The reported potential consequences of clinical application of artificial gametes were extracted from the articles and were grouped into categories by content analysis. Per category, we noted which stakeholders referred to which potential consequences, based on author affiliations and, if applicable, study participants. The systematic search yielded 2424 articles, and 84 studies were included after screening. Nine positive consequences, 21 specific consequences requiring consideration and 22 recommendations referring to clinical application of artificial gametes were documented. All positive consequences, consequences requiring consideration and

Meiosis and Haploid Gametes in the Pathogen Trypanosoma brucei

PubMed Central

Peacock, Lori; Bailey, Mick; Carrington, Mark; Gibson, Wendy

2014-01-01

Summary In eukaryote pathogens, sex is an important driving force in spreading genes for drug resistance, pathogenicity, and virulence [1]. For the parasitic trypanosomes that cause African sleeping sickness, mating occurs during transmission by the tsetse vector [2, 3] and involves meiosis [4], but haploid gametes have not yet been identified. Here, we show that meiosis is a normal part of development in the insect salivary glands for all subspecies of Trypanosoma brucei, including the human pathogens. By observing insect-derived trypanosomes during the window of peak expression of meiosis-specific genes, we identified promastigote-like (PL) cells that interacted with each other via their flagella and underwent fusion, as visualized by the mixing of cytoplasmic red and green fluorescent proteins. PL cells had a short, wide body, a very long anterior flagellum, and either one or two kinetoplasts, but only the anterior kinetoplast was associated with the flagellum. Measurement of nuclear DNA contents showed that PL cells were haploid relative to diploid metacyclics. Trypanosomes are among the earliest diverging eukaryotes, and our results support the hypothesis that meiosis and sexual reproduction are ubiquitous in eukaryotes and likely to have been early innovations [5]. PMID:24388851

Sex differences in parental care: Gametic investment, sexual selection, and social environment.

PubMed

Liker, András; Freckleton, Robert P; Remeš, Vladimir; Székely, Tamás

2015-11-01

Male and female parents often provide different type and amount of care to their offspring. Three major drivers have been proposed to explain parental sex roles: (1) differential gametic investment by males and females that precipitates into sex difference in care, (2) different intensity of sexual selection acting on males and females, and (3) biased social environment that facilitates the more common sex to provide more care. Here, we provide the most comprehensive assessment of these hypotheses using detailed parental care data from 792 bird species covering 126 families. We found no evidence for the gametic investment hypothesis: neither gamete sizes nor gamete production by males relative to females was related to sex difference in parental care. However, sexual selection correlated with parental sex roles, because the male share in care relative to female decreased with both extra-pair paternity and frequency of male polygamy. Parental sex roles were also related to social environment, because male parental care increased with male-biased adult sex ratios (ASRs). Taken together, our results are consistent with recent theories suggesting that gametic investment is not tied to parental sex roles, and highlight the importance of both sexual selection and ASR in influencing parental sex roles. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

9 CFR 93.902 - Ports designated for the importation of live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2010 CFR

2010-01-01

... of live fish, fertilized eggs, and gametes. 93.902 Section 93.902 Animals and Animal Products ANIMAL... importation of live fish, fertilized eggs, and gametes. (a) The following ports are designated as ports of entry for live fish, fertilized eggs, and gametes of SVC-susceptible species imported under this subpart...

9 CFR 93.902 - Ports designated for the importation of live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2011 CFR

2011-01-01

... of live fish, fertilized eggs, and gametes. 93.902 Section 93.902 Animals and Animal Products ANIMAL... importation of live fish, fertilized eggs, and gametes. (a) The following ports are designated as ports of entry for live fish, fertilized eggs, and gametes of SVC-susceptible species imported under this subpart...

Human antibody recognition of antigenic site IV on Pneumovirus fusion proteins.

PubMed

Mousa, Jarrod J; Binshtein, Elad; Human, Stacey; Fong, Rachel H; Alvarado, Gabriela; Doranz, Benjamin J; Moore, Martin L; Ohi, Melanie D; Crowe, James E

2018-02-01

Respiratory syncytial virus (RSV) is a major human pathogen that infects the majority of children by two years of age. The RSV fusion (F) protein is a primary target of human antibodies, and it has several antigenic regions capable of inducing neutralizing antibodies. Antigenic site IV is preserved in both the pre-fusion and post-fusion conformations of RSV F. Antibodies to antigenic site IV have been described that bind and neutralize both RSV and human metapneumovirus (hMPV). To explore the diversity of binding modes at antigenic site IV, we generated a panel of four new human monoclonal antibodies (mAbs) and competition-binding suggested the mAbs bind at antigenic site IV. Mutagenesis experiments revealed that binding and neutralization of two mAbs (3M3 and 6F18) depended on arginine (R) residue R429. We discovered two R429-independent mAbs (17E10 and 2N6) at this site that neutralized an RSV R429A mutant strain, and one of these mAbs (17E10) neutralized both RSV and hMPV. To determine the mechanism of cross-reactivity, we performed competition-binding, recombinant protein mutagenesis, peptide binding, and electron microscopy experiments. It was determined that the human cross-reactive mAb 17E10 binds to RSV F with a binding pose similar to 101F, which may be indicative of cross-reactivity with hMPV F. The data presented provide new concepts in RSV immune recognition and vaccine design, as we describe the novel idea that binding pose may influence mAb cross-reactivity between RSV and hMPV. Characterization of the site IV epitope bound by human antibodies may inform the design of a pan-Pneumovirus vaccine.

A pharmacological study of Arabidopsis cell fusion between the persistent synergid and endosperm.

PubMed

Motomura, Kazuki; Kawashima, Tomokazu; Berger, Frédéric; Kinoshita, Tetsu; Higashiyama, Tetsuya; Maruyama, Daisuke

2018-01-29

Cell fusion is a pivotal process in fertilization and multinucleate cell formation. A plant cell is ubiquitously surrounded by a hard cell wall, and very few cell fusions have been observed except for gamete fusions. We recently reported that the fertilized central cell (the endosperm) absorbs the persistent synergid, a highly differentiated cell necessary for pollen tube attraction. The synergid-endosperm fusion (SE fusion) appears to eliminate the persistent synergid from fertilized ovule in Arabidopsis thaliana Here, we analyzed the effects of various inhibitors on SE fusion in an in vitro culture system. Different from other cell fusions, neither disruption of actin polymerization nor protein secretion impaired SE fusion. However, transcriptional and translational inhibitors decreased the SE fusion success rate and also inhibited endosperm division. Failures of SE fusion and endosperm nuclear proliferation were also induced by roscovitine, an inhibitor of cyclin-dependent kinases (CDK). These data indicate unique aspects of SE fusion such as independence of filamentous actin support and the importance of CDK-mediated mitotic control. © 2018. Published by The Company of Biologists Ltd.

GAMETES: a fast, direct algorithm for generating pure, strict, epistatic models with random architectures.

PubMed

Urbanowicz, Ryan J; Kiralis, Jeff; Sinnott-Armstrong, Nicholas A; Heberling, Tamra; Fisher, Jonathan M; Moore, Jason H

2012-10-01

Geneticists who look beyond single locus disease associations require additional strategies for the detection of complex multi-locus effects. Epistasis, a multi-locus masking effect, presents a particular challenge, and has been the target of bioinformatic development. Thorough evaluation of new algorithms calls for simulation studies in which known disease models are sought. To date, the best methods for generating simulated multi-locus epistatic models rely on genetic algorithms. However, such methods are computationally expensive, difficult to adapt to multiple objectives, and unlikely to yield models with a precise form of epistasis which we refer to as pure and strict. Purely and strictly epistatic models constitute the worst-case in terms of detecting disease associations, since such associations may only be observed if all n-loci are included in the disease model. This makes them an attractive gold standard for simulation studies considering complex multi-locus effects. We introduce GAMETES, a user-friendly software package and algorithm which generates complex biallelic single nucleotide polymorphism (SNP) disease models for simulation studies. GAMETES rapidly and precisely generates random, pure, strict n-locus models with specified genetic constraints. These constraints include heritability, minor allele frequencies of the SNPs, and population prevalence. GAMETES also includes a simple dataset simulation strategy which may be utilized to rapidly generate an archive of simulated datasets for given genetic models. We highlight the utility and limitations of GAMETES with an example simulation study using MDR, an algorithm designed to detect epistasis. GAMETES is a fast, flexible, and precise tool for generating complex n-locus models with random architectures. While GAMETES has a limited ability to generate models with higher heritabilities, it is proficient at generating the lower heritability models typically used in simulation studies evaluating new

Analysis of genetic composition and transmitted parental heterozygosity of natural 2n gametes in Populus tomentosa based on SSR markers.

PubMed

Han, Zhiqiang; Geng, Xining; Du, Kang; Xu, Congping; Yao, Pengqiang; Bai, Fengying; Kang, Xiangyang

2018-06-01

Natural 2n female gametes and transmission of parental heterozygosity by natural 2n gametes in Populus tomentosa are reported for the first time, which provides a new approach to polyploid breeding. Naturally occurring 2n pollen is widespread in Populus tomentosa and plays an important role in polyploid breeding. However, the competitiveness of 2n pollen is lower than that of haploid pollen during pollination and fertilization, so 2n pollen is less efficient at fertilizing haploid female gametes to produce polyploids. In theory, polyploids can also be obtained when 2n female gametes are fertilized by haploid pollen. Thus, the question becomes whether natural 2n female gametes exist in P. tomentosa, which can be answered by examining the genetic composition of natural 2n gametes. In this study, the origin of 87 triploids from the hybrid combination "X-2 × Z-5" was identified by SSR markers and 21% of natural 2n gametes were found to originate from female parents. Four SSR loci with low recombination rates were used to identify the genetic composition of natural 2n gametes. The results showed that the genetic composition of 2n female gametes was mainly characterized by SDR, while 2n male gametes were mainly produced by FDR. Moreover, the transmission of parental heterozygosity by natural 2n gametes, which is significantly different between female and male parents in FDR and SDR types, was analysed using 42 SSR primers. Here, we report naturally occurring 2n female gametes for the first time in P. tomentosa and reveal the genetic constitution and transmitted parental heterozygosity of these gametes. Our results provide a foundation for theoretical research into 2n gametes and their application in new polyploid breeding strategies.

How safe is gamete micromanipulation by laser tweezers?

NASA Astrophysics Data System (ADS)

Koenig, Karsten; Tromberg, Bruce J.; Tadir, Yona; Berns, Michael W.

1998-04-01

Laser tweezers, used as novel sterile micromanipulation tools of living cells, are employed in laser-assisted in vitro fertilization (IVF). For example, controlled spermatozoa transport with 1064 nm tweezers to human egg cells has been performed in European clinics in cases of male infertility. The interaction of approximately 100 mW near infrared (NIR) trapping beams at MW/cm2 intensity with human gametes results in low mean less than 2 K temperature increases and less than 100 pN trapping forces. Therefore, photothermal or photomechanical induced destructive effects appear unlikely. However, the high photon flux densities may induce simultaneous absorption of two NIR photons resulting in nonlinear interactions. These nonlinear interactions imply non-resonant two-photon excitation of endogenous cellular chromophores. In the case of less than 800 nm tweezers, UV- like damage effects may occur. The destructive effect is amplified when multimode cw lasers are used as tweezer sources due to longitudinal mode-beating effects and partial mode- locking. Spermatozoa damage within seconds using 760 nm traps due to formation of unstable ps pulses in a cw Ti:Sa ring laser is demonstrated. We recommend the use of greater than or equal to 800 nm traps for optical gamete micromanipulation. To our opinion, further basic studies on the influence of nonlinear effects of laser tweezers on human gamete are necessary.

Homozygote Depression in Gamete-Derived Dragon-Fruit (Hylocereus) Lines

PubMed Central

Li, Daqing; Arroyave Martinez, Maria F.; Shaked, Ruth; Tel-Zur, Noemi

2018-01-01

Putative gamete-derived progenies from two Hylocereus species, the diploid H. monacanthus and the tetraploid H. megalanthus, were studied with the dual aims to confirm their gamete origin and to evaluate their potential use as genetic resources. An additional goal was to determine the origin (allotetraploid vs. autotetraploid) of H. megalanthus by exploring morphological variations in the di-haploid (2x) H. megalanthus progeny. Gamete origin was proved in all five H. monacanthus lines obtained and in 49 of the 70 H. megalanthus lines by using flow cytometry and simple sequence repeat (SSR) markers. The five double-haploid (2x) H. monacanthus lines showed low vigor and abnormal flower development, with malformed ovules and aborted pollen grains. Only one flower set fruit, giving several viable seeds. For H. megalanthus, both abnormal ovules and defective anthers were observed in the di-haploid (2x) and double di-haploid (4x) lines. Among the 46 di-haploid lines, only 14 set fruit. Another 13 di-haploid lines formed flower buds that abscised before anthesis or soon after pollination. The severe sterility of the double-haploid H. monacanthus and the reduced fertility of all the di-haploid and double di-haploid H. megalanthus lines can be linked to their reduced heterozygosity, which drastically affected the development of normal female and male organs. We thus concluded that chromosome doubling, as occurred spontaneously in the double-haploid H. monacanthus and the double di-haploid H. megalanthus, is not sufficient to restore fertility in Hylocereus. We also observed very low gametoclonal variation among the di-haploid (2x) H. megalanthus lines, a finding that supported an autotetraploid, rather than an allotetraploid, origin of this species. Nonetheless, despite the above-described challenging limitations, these gamete-derived lines are currently being bred as the seed parent, offering unique possibilities for genetic research and additional breeding. PMID:29354138

Meiosis and haploid gametes in the pathogen Trypanosoma brucei.

PubMed

Peacock, Lori; Bailey, Mick; Carrington, Mark; Gibson, Wendy

2014-01-20

In eukaryote pathogens, sex is an important driving force in spreading genes for drug resistance, pathogenicity, and virulence. For the parasitic trypanosomes that cause African sleeping sickness, mating occurs during transmission by the tsetse vector and involves meiosis, but haploid gametes have not yet been identified. Here, we show that meiosis is a normal part of development in the insect salivary glands for all subspecies of Trypanosoma brucei, including the human pathogens. By observing insect-derived trypanosomes during the window of peak expression of meiosis-specific genes, we identified promastigote-like (PL) cells that interacted with each other via their flagella and underwent fusion, as visualized by the mixing of cytoplasmic red and green fluorescent proteins. PL cells had a short, wide body, a very long anterior flagellum, and either one or two kinetoplasts, but only the anterior kinetoplast was associated with the flagellum. Measurement of nuclear DNA contents showed that PL cells were haploid relative to diploid metacyclics. Trypanosomes are among the earliest diverging eukaryotes, and our results support the hypothesis that meiosis and sexual reproduction are ubiquitous in eukaryotes and likely to have been early innovations. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Stem cells to gametes: how far should we go?

PubMed

Whittaker, Peter

2007-03-01

Murine embryonic stem cells have recently been shown to be capable of differentiating in vitro into oocytes or sperm. Should these findings be duplicated using human embryonic stem cells, this would raise a number of social and ethical concerns, some specific to these particular developments, others shared with other aspects of stem cell research. This review outlines the properties of stem cells and their conversion to gametes. Concerns raised include embryo destruction, quality of gametes derived in this way, possibility for children with two male biological parents, movement towards germ line gene therapy and 'designer babies', and the future impacts on health service provisions. It is important that public discussion of some of these issues should take place.

Meiosis, unreduced gametes, and parthenogenesis: implications for engineering clonal seed formation in crops.

PubMed

Ronceret, Arnaud; Vielle-Calzada, Jean-Philippe

2015-06-01

Meiosis and unreduced gametes. Sexual flowering plants produce meiotically derived cells that give rise to the male and female haploid gametophytic phase. In the ovule, usually a single precursor (the megaspore mother cell) undergoes meiosis to form four haploid megaspores; however, numerous mutants result in the formation of unreduced gametes, sometimes showing female specificity, a phenomenon reminiscent of the initiation of gametophytic apomixis. Here, we review the developmental events that occur during female meiosis and megasporogenesis at the light of current possibilities to engineer unreduced gamete formation. We also provide an overview of the current understanding of mechanisms leading to parthenogenesis and discuss some of the conceptual implications for attempting the induction of clonal seed production in cultivated plants.

A protein isolated from human oviductal tissue in vitro secretion, identified as human lactoferrin, interacts with spermatozoa and oocytes and modulates gamete interaction.

PubMed

Zumoffen, C M; Gil, R; Caille, A M; Morente, C; Munuce, M J; Ghersevich, S A

2013-05-01

Is lactoferrin (LF) (detected in oviductal secretion) able to bind to oocytes and sperm and modulate gamete interaction? LF binds to zona pellucida (ZP) and spermatozoa (depending upon the capacitation stage and acrosome status) and inhibits gamete interaction in vitro. Proteins from human oviductal tissue secretion modulate gamete interaction and parameters of sperm function in vitro and some of them bind to sperm, but they remain to be isolated and identified. Proteins were isolated from human oviductal tissue secretion using their sperm membrane binding ability. One of the isolated proteins was identified as human LF and immunolocalized in tubal tissues. LF expression was analyzed in native oviductal fluid and oviduct epithelial cells (at different phases of the menstrual cycle: proliferative, periovulatory and secretory). In addition, the LF binding sites on spermatozoa (at different capacitation and acrosome reaction stages) and on ZP and the dose-dependent effect of LF on gamete interaction were investigated. All experiments were performed at least three times. Tubal tissues obtained from premenopausal patients (scheduled for hysterectomy, n = 23) were cultured in DMEM/Ham's F12 medium and conditioned media (CM) were collected. Motile spermatozoa were obtained by swim-up from normozoospermic semen samples from healthy donors (n = 4). An affinity chromatography with sperm membrane extracts was used to isolate proteins from CM. Isolated proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophresis and further identified by nano liquid chromatography tandem mass spectrometry peptide sequencing. The presence of LF in oviductal tissue was investigated by immunohistochemistry and immunofluorescence and was detected in native oviductal fluid and oviduct epithelial cells homogenates by western blot. LF binding sites on gametes were investigated by incubating gametes with the protein coupled to fluorescein isothiocyanate (FITC). The acrosome

Influence of acylation sites of influenza B virus hemagglutinin on fusion pore formation and dilation.

PubMed

Ujike, Makoto; Nakajima, Katsuhisa; Nobusawa, Eri

2004-11-01

The cytoplasmic tail (CT) of hemagglutinin (HA) of influenza B virus (BHA) contains at positions 578 and 581 two highly conserved cysteine residues (Cys578 and Cys581) that are modified with palmitic acid (PA) through a thioester linkage. To investigate the role of PA in the fusion activity of BHA, site-specific mutagenesis was performed with influenza B virus B/Kanagawa/73 HA cDNA. All of the HA mutants were expressed on Cos cells by an expression vector. The membrane fusion ability of the HA mutants at a low pH was quantitatively examined with lipid (octadecyl rhodamine B chloride) and aqueous (calcein) dye transfer assays and with the syncytium formation assay. Two deacylation mutants lacking a CT or carrying serine residues substituting for Cys578 and Cys581 promoted full fusion. However, one of the single-acylation-site mutants, C6, in which Cys581 is replaced with serine, promoted hemifusion but not pore formation. In contrast, four other single-acylation-site mutants that have a sole cysteine residue in the CT at position 575, 577, 579, or 581 promoted full fusion. The impaired pore-forming ability of C6 was improved by amino acid substitution between residues 578 and 582 or by deletion of the carboxy-terminal leucine at position 582. Syncytium-forming ability, however, was not adequately restored by these mutations. These facts indicated that the acylation was not significant in membrane fusion by BHA but that pore formation and pore dilation were appreciably affected by the particular amino acid sequence of the CT and the existence of a single acylation site in CT residue 578.

Gamete donors' motivation in a Swedish national sample: is there any ambivalence? A descriptive study.

PubMed

Svanberg, Agneta Skoog; Lampic, Claudia; Gejervall, Ann-Louise; Geijerwall, Ann-Louise; Gudmundsson, Johannes; Karlström, Per-Olof; Solensten, Nils-Gunnar; Sydsjö, Gunilla

2012-08-01

To study donors' motivation and ambivalence before donation of gametes. Cross-sectional study. Seven Swedish university hospital clinics. Sample. Of the 220 eligible oocyte donors and 156 eligible sperm donors who were approached, 181 (82%) oocyte donors and 119 (76%) sperm donors agreed to participate. Gamete donors completed a questionnaire in the clinic prior to the donation. Motives and ambivalence towards donation. In general, gamete donors donated for altruistic reasons (95%). A greater percentage of oocyte than sperm donors had a personal experience of biological children, which motivated them to donate (65 vs. 32%). A greater percentage of sperm donors compared with oocyte donors were curious about their own fertility (24 vs. 9%), and they also believed that they were contributing what they regarded as their own good genes to other couples (45 vs. 20%). Prior to donation, potential sperm donors were more ambivalent towards donating than were oocyte donors (39 and 21%, p < 0.001). The motives to donate gametes are mainly altruistic. We conclude that men and women differ in their view towards donating gametes. Sperm donors had a higher degree of ambivalent feelings towards donation than oocyte donors. © 2012 The Authors Acta Obstetricia et Gynecologica Scandinavica© 2012 Nordic Federation of Societies of Obstetrics and Gynecology.

Purple sea urchin Strongylocentrotus purpuratus gamete manipulation using optical trapping and microfluidics

NASA Astrophysics Data System (ADS)

Chandsawangbhuwana, Charlie; Shi, Linda Z.; Zhu, Qingyuan; Berns, Michael W.

2013-04-01

A system has been developed that allows for optical and fluidic manipulation of gametes. The optical manipulation is performed by using a single-point gradient trap with a 40× oil immersion PH3 1.3 NA objective on a Zeiss inverted microscope. The fluidic manipulation is performed by using a custom microfluidic chamber designed to fit into the short working distance between the condenser and objective. The system is validated using purple sea urchin Strongylocentrotus purpuratus gametes and has the potential to be used for mammalian in vitro fertilization and animal husbandry.

Cytological, molecular mechanisms and temperature stress regulating production of diploid male gametes in Dianthus caryophyllus L.

PubMed

Zhou, Xuhong; Mo, Xijun; Gui, Min; Wu, Xuewei; Jiang, Yalian; Ma, Lulin; Shi, Ziming; Luo, Ying; Tang, Wenru

2015-12-01

In plant evolution, because of its key role in sexual polyploidization or whole genome duplication events, diploid gamete formation is considered as an important component in diversification and speciation. Environmental stress often triggers unreduced gamete production. However, the molecular, cellular mechanisms and adverse temperature regulating diplogamete production in carnation remain poorly understood. Here, we investigate the cytological basis for 2n male gamete formation and describe the isolation and characterization of the first gene, DcPS1 (Dianthus Caryophyllus Parallel Spindle 1). In addition, we analyze influence of temperature stress on diploid gamete formation and transcript levels of DcPS1. Cytological evidence indicated that 2n male gamete formation is attributable to abnormal spindle orientation at male meiosis II. DcPS1 protein is conserved throughout the plant kingdom and carries domains suggestive of a regulatory function. DcPS1 expression analysis show DcPS1 gene probably have a role in 2n pollen formation. Unreduced pollen formation in various cultivation was sensitive to high or low temperature which was probably regulated by the level of DcPS1 transcripts. In a broader perspective, these findings can have potential applications in fundamental polyploidization research and plant breeding programs. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Fragile sites, dysfunctional telomere and chromosome fusions: What is 5S rDNA role?

PubMed

Barros, Alain Victor; Wolski, Michele Andressa Vier; Nogaroto, Viviane; Almeida, Mara Cristina; Moreira-Filho, Orlando; Vicari, Marcelo Ricardo

2017-04-15

Repetitive DNA regions are known as fragile chromosomal sites which present a high flexibility and low stability. Our focus was characterize fragile sites in 5S rDNA regions. The Ancistrus sp. species shows a diploid number of 50 and an indicative Robertsonian fusion at chromosomal pair 1. Two sequences of 5S rDNA were identified: 5S.1 rDNA and 5S.2 rDNA. The first sequence gathers the necessary structures to gene expression and shows a functional secondary structure prediction. Otherwise, the 5S.2 rDNA sequence does not contain the upstream sequences that are required to expression, furthermore its structure prediction reveals a nonfunctional ribosomal RNA. The chromosomal mapping revealed several 5S.1 and 5S.2 rDNA clusters. In addition, the 5S.2 rDNA clusters were found in acrocentric and metacentric chromosomes proximal regions. The pair 1 5S.2 rDNA cluster is co-located with interstitial telomeric sites (ITS). Our results indicate that its clusters are hotspots to chromosomal breaks. During the meiotic prophase bouquet arrangement, double strand breaks (DSBs) at proximal 5S.2 rDNA of acrocentric chromosomes could lead to homologous and non-homologous repair mechanisms as Robertsonian fusions. Still, ITS sites provides chromosomal instability, resulting in telomeric recombination via TRF2 shelterin protein and a series of breakage-fusion-bridge cycles. Our proposal is that 5S rDNA derived sequences, act as chromosomal fragile sites in association with some chromosomal rearrangements of Loricariidae. Copyright © 2017 Elsevier B.V. All rights reserved.

Gametes or organs? How should we legally classify ovaries used for transplantation in the USA?

PubMed Central

Campo-Engelstein, Lisa

2011-01-01

Ovarian tissue transplantation is an experimental procedure that can be used to treat both infertility and premature menopause. Working within the current legal framework in the USA, I examine whether ovarian tissue should be legally treated like gametes or organs in the case of ovarian tissue transplantation between two women. One option is to base classification upon its intended use: ovarian tissue used to treat infertility would be classified like gametes, and ovarian tissue used to treat premature menopause would be classified like organs. In the end, however, I argue that this approach will not work because it engenders too many legal, cultural and logistical concerns and that, at least for the near future, we should treat ovarian tissue like gametes. PMID:21245477

Fusion of Geophysical Images in the Study of Archaeological Sites

NASA Astrophysics Data System (ADS)

Karamitrou, A. A.; Petrou, M.; Tsokas, G. N.

2011-12-01

This paper presents results from different fusion techniques between geophysical images from different modalities in order to combine them into one image with higher information content than the two original images independently. The resultant image will be useful for the detection and mapping of buried archaeological relics. The examined archaeological area is situated in Kampana site (NE Greece) near the ancient theater of Maronia city. Archaeological excavations revealed an ancient theater, an aristocratic house and the temple of the ancient Greek God Dionysus. Numerous ceramic objects found in the broader area indicated the probability of the existence of buried urban structure. In order to accurately locate and map the latter, geophysical measurements performed with the use of the magnetic method (vertical gradient of the magnetic field) and of the electrical method (apparent resistivity). We performed a semi-stochastic pixel based registration method between the geophysical images in order to fine register them by correcting their local spatial offsets produced by the use of hand held devices. After this procedure we applied to the registered images three different fusion approaches. Image fusion is a relatively new technique that not only allows integration of different information sources, but also takes advantage of the spatial and spectral resolution as well as the orientation characteristics of each image. We have used three different fusion techniques, fusion with mean values, with wavelets by enhancing selected frequency bands and curvelets giving emphasis at specific bands and angles (according the expecting orientation of the relics). In all three cases the fused images gave significantly better results than each of the original geophysical images separately. The comparison of the results of the three different approaches showed that the fusion with the use of curvelets, giving emphasis at the features' orientation, seems to give the best fused image

Pushing the dead into the next reproductive frontier: post mortem gamete retrieval under the uniform anatomical gift act.

PubMed

Spielman, Bethany

2009-01-01

In re Matter of Daniel Thomas Christy authorized post mortem gamete retrieval under the most recent revision of the Uniform Anatomical Gift Act. This article recommends that the National Conference of Commissioners on Uniform State Laws explicitly address the issue of post mortem gamete retrieval for reproductive purposes; that legislators specify whether their states will follow the Christy ruling; and that ethics committees and consultants prepare for the questions about human identity and self determination that post mortem gamete retrieval raises.

Data fusion strategies for hazard detection and safe site selection for planetary and small body landings

NASA Astrophysics Data System (ADS)

Câmara, F.; Oliveira, J.; Hormigo, T.; Araújo, J.; Ribeiro, R.; Falcão, A.; Gomes, M.; Dubois-Matra, O.; Vijendran, S.

2015-06-01

This paper discusses the design and evaluation of data fusion strategies to perform tiered fusion of several heterogeneous sensors and a priori data. The aim is to increase robustness and performance of hazard detection and avoidance systems, while enabling safe planetary and small body landings anytime, anywhere. The focus is on Mars and asteroid landing mission scenarios and three distinct data fusion algorithms are introduced and compared. The first algorithm consists of a hybrid camera-LIDAR hazard detection and avoidance system, the H2DAS, in which data fusion is performed at both sensor-level data (reconstruction of the point cloud obtained with a scanning LIDAR using the navigation motion states and correcting the image for motion compensation using IMU data), feature-level data (concatenation of multiple digital elevation maps, obtained from consecutive LIDAR images, to achieve higher accuracy and resolution maps while enabling relative positioning) as well as decision-level data (fusing hazard maps from multiple sensors onto a single image space, with a single grid orientation and spacing). The second method presented is a hybrid reasoning fusion, the HRF, in which innovative algorithms replace the decision-level functions of the previous method, by combining three different reasoning engines—a fuzzy reasoning engine, a probabilistic reasoning engine and an evidential reasoning engine—to produce safety maps. Finally, the third method presented is called Intelligent Planetary Site Selection, the IPSIS, an innovative multi-criteria, dynamic decision-level data fusion algorithm that takes into account historical information for the selection of landing sites and a piloting function with a non-exhaustive landing site search capability, i.e., capable of finding local optima by searching a reduced set of global maps. All the discussed data fusion strategies and algorithms have been integrated, verified and validated in a closed-loop simulation environment

SCAR/WAVE and Arp2/3 are critical for cytoskeletal remodeling at the site of myoblast fusion

PubMed Central

Richardson, Brian E.; Beckett, Karen; Nowak, Scott J.; Baylies, Mary K.

2010-01-01

Summary Myoblast fusion is critical for formation and repair of skeletal muscle. Here we show that active remodeling of the actin cytoskeleton is essential for fusion in Drosophila. Using live imaging, we have identified a dynamic F-actin accumulation (actin focus) at the site of fusion. Dissolution of the actin focus directly precedes a fusion event. Whereas several known fusion components regulate these actin foci, others target additional behaviors required for fusion. Mutations in kette/Nap1, an actin polymerization regulator, lead to enlarged foci that do not dissolve, consistent with the observed block in fusion. Kette is required to positively regulate SCAR/WAVE, which in turn activates the Arp2/3 complex. Mutants in SCAR and Arp2/3 have a fusion block and foci phenotype, suggesting that Kette-SCAR-Arp2/3 participate in an actin polymerization event required for focus dissolution. Our data identify a new paradigm for understanding the mechanisms underlying fusion in myoblasts and other tissues. PMID:18003739

Gendering gametes: The unequal contributions of sperm and egg donors.

PubMed

Hertz, Rosanna; Nelson, Margaret K; Kramer, Wendy

2015-12-01

This paper compares three groups of gestational mothers who relied on gametes from donors they did not know. The three groups are women who have conceived with donor sperm and their own eggs, women who have conceived with donor eggs and a partner's sperm, and women who have conceived with embryos composed of both donor eggs and donor sperm. The paper explores three issues. First, it considers whether intending parents select sperm and egg donors for different attributes both when they are chosen as the only donor and when they are chosen as donors contributing to an entire embryo. Second, it examines how women imagine the donor. Finally, it looks at how women conceptualize the donor as an individual who contributes to their child's characteristics. Two significant findings emerged in this analysis of survey data. First, the data show that gametes are gendered with different attributes both when those gametes are separate and even more so when seen as complementary parts of a whole. Second, the data show that women minimize the impact of the egg donor (both when a sole contribution and especially when part of the complementary whole) and thus ignore the influence or impact of the egg donor relative to how they make sense of the influence or impact of the sperm donor. The data for this study comes from an online survey developed by the authors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Using stem cell-derived gametes for same-sex reproduction: an alternative scenario.

PubMed

Segers, Seppe; Mertes, Heidi; Pennings, Guido; de Wert, Guido; Dondorp, Wybo

2017-10-01

It has been suggested that future application of stem-cell derived gametes (SCD-gametes) might lead to the possibility for same-sex couples to have genetically related children. Still, for this to become possible, the technique of gamete derivation and techniques of reprogramming somatic cells to a pluripotent state (directly or via somatic cell nuclear transfer) would have to be perfected. Moreover, egg cells would have to be derived from male cells and sperm cells from female cells, which is believed to be particularly difficult, if not impossible. We suggest a more plausible scenario to provide same-sex couples with the possibility to parent a child who is genetically related to both parents. Although technical feasibility is an advantage (also in terms of safety), disadvantages are that cooperation of a donor of the opposite sex is still required and that the partners are genetically linked to the resulting child in a different degree. However, since in our scenario the donor's genetic contribution would not outweigh any of the parents' genetic contribution, this alternative route may ease the fear for a possible parental claim by the donor. Like many other applications in the field of infertility treatment, the goal to create SCD-gametes for reproductive purposes is largely based on the high value attributed to genetic parenthood. Although we believe that genetic relatedness is neither a necessary nor a sufficient condition for 'good' parenthood, we do believe that many people may consider our scenario a welcome alternative. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

A relationship between traditionally motivated patterns and gamete donation and surrogacy in urban areas of Greece.

PubMed

Chliaoutakis, Joannes E

2002-08-01

Although gamete receipt or donation has become an integral part of infertility management, previous research in the field of social attitudes and intention to use medical technologies is limited. The aim of this paper was to investigate people's intentions to receive or donate sperm, oocyte or uterus (surrogacy) and to identify possible motivational patterns explaining this intention. Personal interviews were conducted with 365 men and women of reproductive age (18-45 years). Stratified random sampling was performed to select the men and women for interview. The content of the instrument used was derived from in-depth qualitative interviews with physicians experienced in assisted reproductive technologies, as well as from people who had recourse to gamete donation and surrogacy. The results obtained highlighted the following major aspects: (i) approximately 50% of the survey's participants would be prepared to receive/donate sperm and oocyte; (ii) the results from multiple regression analysis suggest that the 'traditional gender roles' pattern is positively associated with 'intention to use gamete donation and surrogacy'. On the contrary, 'confidence in emotional relationship' is negatively associated with 'intention to use gamete donation and surrogacy, and (iii) men are more likely than women to report 'intention to use gamete donation and surrogacy'. These data suggest that specific motivational patterns of the population need to be thoroughly analysed and taken into consideration, in order that appropriate counselling be addressed to individuals and couples.

The long path to pregnancy: early experience with dual anonymous gamete donation in a European in vitro fertilisation referral centre.

PubMed

Sills, Eric Scott; Mykhaylyshyn, Lyubov O; Dorofeyeva, Ulyana S; Walsh, David J; Salma, Umme; Omar, Ahmed B; Coull, Graham D; David, Ileana A; Brickell, Kathy M; Tsar, Olga M; Walsh, Anthony Ph

2010-08-11

This investigation describes features of patients undergoing in vitro fertilisation (IVF) and embryo transfer (ET) where both gametes were obtained from anonymous donors. Gamete unsuitability or loss was confirmed in both members of seven otherwise healthy couples presenting for reproductive endocrinology consultation over a 12-month interval in Ireland. IVF was undertaken with fresh oocytes provided by anonymous donors in Ukraine; frozen sperm (anonymous donor) was obtained from a licensed tissue establishment. For recipients, saline-enhanced sonography was used to assess intrauterine contour with endometrial preparation via transdermal estrogen. Among commissioning couples, mean+/-SD female and male age was 41.9 +/- 3.7 and 44.6 +/- 3.5 yrs, respectively. During this period, female age for non dual anonymous gamete donation IVF patients was 37.9 +/- 3 yrs (p < 0.001). Infertility duration was >/=3 yrs for couples enrolling in dual gamete donation, and each had >/=2 prior failed fertility treatments using native oocytes. All seven recipient couples proceeded to embryo transfer, although one patient had two transfers. Clinical pregnancy was achieved for 5/7 (71.4%) patients. Non-transferred cryopreserved embryos were available for all seven couples. Mean age of females undergoing dual anonymous donor gamete donation with IVF is significantly higher than the background IVF patient population. Even when neither partner is able to contribute any gametes for IVF, the clinical pregnancy rate per transfer can be satisfactory if both anonymous egg and sperm donation are used concurrently. Our report emphasises the role of pre-treatment counselling in dual anonymous gamete donation, and presents a coordinated screening and treatment approach in IVF where this option may be contemplated.

Gamete and Embryo Donation and Surrogacy in Australia: The Social Context and Regulatory Framework

PubMed Central

Hammarberg, Karin; Johnson, Louise; Petrillo, Tracey

2011-01-01

The social and legal acceptability of third-party reproduction varies around the world. In Australia, gamete and embryo donation and surrogacy are permitted within the regulatory framework set out by federal and state governments. The aim of this paper is to describe the social context and regulatory framework for third-party reproduction in Australia. This is a review of current laws and regulations related to third-party reproduction in Australia. Although subtle between-state differences exist, third-party reproduction is by and large a socially acceptable and legally permissible way to form a family throughout Australia. The overarching principles that govern the practice of third-party reproduction are altruism; the right of donorconceived people to be informed of their biological origins; and the provision of comprehensive counselling about the social, psychological, physical, ethical, financial and legal implications of third-party reproduction to those considering donating or receiving gametes or embryos and entering surrogacy arrangements. These principles ensure that donors are not motivated by financial gain, donor offspring can identify and meet with the person or persons who donated gametes or embryos, and prospective donors and recipients are aware of and have carefully considered the potential consequences of third-party reproduction. Australian state laws and federal guidelines prohibit commercial and anonymous third-party reproduction; mandate counselling of all parties involved in gamete and embryo donation and surrogacy arrangements; and require clinics to keep records with identifying and non- identifying information about the donor/s to allow donor-conceived offspring to trace their biological origins. PMID:24851179

Gamete and embryo donation and surrogacy in australia: the social context and regulatory framework.

PubMed

Hammarberg, Karin; Johnson, Louise; Petrillo, Tracey

2011-01-01

The social and legal acceptability of third-party reproduction varies around the world. In Australia, gamete and embryo donation and surrogacy are permitted within the regulatory framework set out by federal and state governments. The aim of this paper is to describe the social context and regulatory framework for third-party reproduction in Australia. This is a review of current laws and regulations related to third-party reproduction in Australia. Although subtle between-state differences exist, third-party reproduction is by and large a socially acceptable and legally permissible way to form a family throughout Australia. The overarching principles that govern the practice of third-party reproduction are altruism; the right of donorconceived people to be informed of their biological origins; and the provision of comprehensive counselling about the social, psychological, physical, ethical, financial and legal implications of third-party reproduction to those considering donating or receiving gametes or embryos and entering surrogacy arrangements. These principles ensure that donors are not motivated by financial gain, donor offspring can identify and meet with the person or persons who donated gametes or embryos, and prospective donors and recipients are aware of and have carefully considered the potential consequences of third-party reproduction. Australian state laws and federal guidelines prohibit commercial and anonymous third-party reproduction; mandate counselling of all parties involved in gamete and embryo donation and surrogacy arrangements; and require clinics to keep records with identifying and non- identifying information about the donor/s to allow donor-conceived offspring to trace their biological origins.

[Gamete donation contracts: gift of life or sale of genetic material?].

PubMed

Raposo, Vera Lúcia

2012-01-01

When science made possible to overcome the biological limitation to infertility, gamete had become a "valuable good". Therefore, lawyers are asked to define their juridical status, their modality of transference, their possible uses and the legal protection reserved to them.

The long path to pregnancy: early experience with dual anonymous gamete donation in a European in vitro fertilisation referral centre

PubMed Central

2010-01-01

Background This investigation describes features of patients undergoing in vitro fertilisation (IVF) and embryo transfer (ET) where both gametes were obtained from anonymous donors. Methods Gamete unsuitability or loss was confirmed in both members of seven otherwise healthy couples presenting for reproductive endocrinology consultation over a 12-month interval in Ireland. IVF was undertaken with fresh oocytes provided by anonymous donors in Ukraine; frozen sperm (anonymous donor) was obtained from a licensed tissue establishment. For recipients, saline-enhanced sonography was used to assess intrauterine contour with endometrial preparation via transdermal estrogen. Results Among commissioning couples, mean±SD female and male age was 41.9 ± 3.7 and 44.6 ± 3.5 yrs, respectively. During this period, female age for non dual anonymous gamete donation IVF patients was 37.9 ± 3 yrs (p < 0.001). Infertility duration was ≥3 yrs for couples enrolling in dual gamete donation, and each had ≥2 prior failed fertility treatments using native oocytes. All seven recipient couples proceeded to embryo transfer, although one patient had two transfers. Clinical pregnancy was achieved for 5/7 (71.4%) patients. Non-transferred cryopreserved embryos were available for all seven couples. Conclusions Mean age of females undergoing dual anonymous donor gamete donation with IVF is significantly higher than the background IVF patient population. Even when neither partner is able to contribute any gametes for IVF, the clinical pregnancy rate per transfer can be satisfactory if both anonymous egg and sperm donation are used concurrently. Our report emphasises the role of pre-treatment counselling in dual anonymous gamete donation, and presents a coordinated screening and treatment approach in IVF where this option may be contemplated. PMID:20701806

In vitro gamete derivation from pluripotent stem cells: progress and perspective.

PubMed

Nagano, Makoto C

2007-04-01

Germ cells constitute a highly specialized cell population that is indispensable for the continuation and evolution of the species. Recently, several research groups have shown that these unique cells can be produced in vitro from pluripotent stem cells. Furthermore, live births of offspring using induced germ cells have been reported in one study. These results suggest that it may be possible to investigate germ cell development ex vivo and to establish novel reproductive technologies. To this end, it is critical to assess if gamete induction processes in vitro faithfully recapitulate normal germ cell development in vivo. Here, this issue is discussed with a focus on the germ line specification and the sex-specific development of pre- and postnatal germ cells. The aim of this paper is to concisely summarize the past progress and to present some future issues for the investigation into in vitro gamete production from pluripotent stem cells.

Making muslim babies: Ivf and gamete donation in sunni versus shi’a islam

PubMed Central

2006-01-01

Medical anthropological research on science, biotechnology, and religion has focused on the “local moral worlds” of men and women as they make difficult decisions regarding their health and the beginnings and endings of human life. This paper focuses on the local moral worlds of infertile Muslims as they attempt to make, in the religiously correct fashion, Muslim babies at in vitro fertilization (IVF) clinics in Egypt and Lebanon. As early as 1980, authoritative fatwas issued from Egypt’s famed Al-Azhar University suggested that IVF and similar technologies are permissible as long as they do not involve any form of third-party donation (of sperm, eggs, embryos, or uteruses). Since the late 1990s, however, divergences in opinion over third-party gamete donation have occurred between Sunni and Shi’ite Muslims, with Iran’s leading ayatollah permitting gamete donation under certain conditions. This Iranian fatwa has had profound implications for the country of Lebanon, where a Shi’ite majority also seeks IVF services. Based on three periods of ethnographic research in Egyptian and Lebanese IVF clinics, this paper explores official and unofficial religious discourses surrounding the practice of IVF and third-party donation in the Muslim world, as well as the gender implications of gamete donation for Muslim marriages. PMID:17051430

Evolution of hierarchical cytoplasmic inheritance in the plasmodial slime mold Physarum polycephalum.

PubMed

Iwanaga, Akiko; Sasaki, Akira

2004-04-01

A striking linear dominance relationship for uniparental mitochondrial transmission is known between many mating types of plasmodial slime mold Physarum polycephalum. We herein examine how such hierarchical cytoplasmic inheritance evolves in isogamous organisms with many self-incompatible mating types. We assume that a nuclear locus determines the mating type of gametes and that another nuclear locus controls the digestion of mitochondria DNAs (mtDNAs) of the recipient gamete after fusion. We then examine the coupled genetic dynamics for the evolution of self-incompatible mating types and biased mitochondrial transmission between them. In Physarum, a multiallelic nuclear locus matA controls both the mating type of the gametes and the selective elimination of the mtDNA in the zygotes. We theoretically examine two potential mechanisms that might be responsible for the preferential digestion of mitochondria in the zygote. In the first model, the preferential digestion of mitochondria is assumed to be the outcome of differential expression levels of a suppressor gene carried by each gamete (suppression-power model). In the second model (site-specific nuclease model), the digestion of mtDNAs is assumed to be due to their cleavage by a site-specific nuclease that cuts the mtDNA at unmethylated recognition sites. Also assumed is that the mtDNAs are methylated at the same recognition site prior to the fusion, thereby being protected against the nuclease of the same gamete, and that the suppressor alleles convey information for the recognition sequences of nuclease and methylase. In both models, we found that a linear dominance hierarchy evolves as a consequence of the buildup of a strong linkage disequilibrium between the mating-type locus and the suppressor locus, though it fails to evolve if the recombination rate between the two loci is larger than a threshold. This threshold recombination rate depends on the number of mating types and the degree of fitness reduction in

GENDER-SPECIFIC DIFFERENCES IN THE RESPONSE OF MATURING GAMETES TO TOXIC INSULT

EPA Science Inventory

GENDER-SPECIFIC DIFFERENCES IN THE RESPONSE OF MATURING GAMETES TO TOXIC INSULT

Sally D. Perreault, U. S. Environmental Toxicology Division, National Health and Environmental Effects Research Laboratory, Reproductive Toxicology Division, Research Triangle Park, NC 27711

When genes move farther than offspring: gene flow by male gamete dispersal in the highly philopatric bat species Thyroptera tricolor.

PubMed

Buchalski, M R; Chaverri, G; Vonhof, M J

2014-02-01

For species characterized by philopatry of both sexes, mate selection represents an important behaviour for inbreeding avoidance, yet the implications for gene flow are rarely quantified. Here, we present evidence of male gamete-mediated gene flow resulting from extra-group mating in Spix's disc-winged bat, Thyroptera tricolor, a species which demonstrates all-offspring philopatry. We used microsatellite and capture-recapture data to characterize social group structure and the distribution of mated pairs at two sites in southwestern Costa Rica over four breeding seasons. Relatedness and genetic spatial autocorrelation analyses indicated strong kinship within groups and over short distances (<50 m), resulting from matrilineal group structure and small roosting home ranges (~0.2 ha). Despite high relatedness among-group members, observed inbreeding coefficients were low (FIS  = 0.010 and 0.037). Parentage analysis indicated mothers and offspring belonged to the same social group, while fathers belonged to different groups, separated by large distances (~500 m) when compared to roosting home ranges. Simulated random mating indicated mate choice was not based on intermediate levels of relatedness, and mated pairs were less related than adults within social groups on average. Isolation-by-distance (IBD) models of genetic neighbourhood area based on father-offspring distances provided direct estimates of mean gamete dispersal distances (r^) > 10 roosting home range equivalents. Indirect estimates based on genetic distance provided even larger estimates of r^, indicating direct estimates were biased low. These results suggest extra-group mating reduces the incidence of inbreeding in T. tricolor, and male gamete dispersal facilitates gene flow in lieu of natal dispersal of young. © 2013 John Wiley & Sons Ltd.

Property rights in human gametes in Australia.

PubMed

White, Vanessa

2013-03-01

It has long been a basic tenet of the common law that there can be no property interest in human bodies or body parts. However, exceptions to the rule have been recognised from the mid-19th century and developed over time. In the early 21st century, there have been interesting developments in the common law of Australia and England, with Australian Supreme Court judges and the English Court of Appeal casting aside existing exceptions, and finding property rights in human body parts, including gametes, by relying instead on a "rational" and "logical" basis to identify property interests in human body parts.

Hold on: females modulate sperm depletion from storage sites in the fly Drosophila melanogaster.

PubMed

Bloch Qazi, Margaret C; Hogdal, Leah

2010-09-01

Among many species of insects, females gain fitness benefits by producing numerous offspring. Yet actions related to producing numerous offspring such as mating with multiple males, producing oocytes and placing offspring in sub-optimal environments incur costs. Females can decrease the magnitude of these costs by retaining gametes when suitable oviposition sites are absent. We used the pomace fly, Drosophila melanogaster, to explore how the availability of fresh feeding/oviposition medium influenced female fitness via changes in offspring survivorship and the modulation of gamete release. Availability of fresh medium affected the absolute number and temporal production of offspring. This outcome was attributable to both decreased larval survival under crowded conditions and to female modulation of gamete release. Direct examination of the number of sperm retained among the different female storage organs revealed that females 'hold on' to sperm, retaining more sperm in storage, disproportionately within the spermathecae, when exposed infrequently to fresh medium. Despite this retention, females with lower rates of storage depletion exhibited decreased sperm use efficiency shortly after mating. This study provides direct evidence that females influence the rate of sperm depletion from specific storage sites in a way that can affect both female and male fitness. The possible adaptive significance of selective gamete utilization by female Drosophila includes lowering costs associated with frequent remating and larval overcrowding when oviposition sites are limiting, as well as potentially influencing paternity when females store sperm from multiple males.

Dynamics of gamete production and mating in the parasitic protist Trypanosoma brucei.

PubMed

Peacock, Lori; Bailey, Mick; Gibson, Wendy

2016-07-20

Sexual reproduction in Plasmodium falciparum and Trypanosoma brucei occurs in the insect vector and is important in generating hybrid strains with different combinations of parental characteristics. Production of hybrid parasite genotypes depends on the likelihood of co-infection of the vector with multiple strains. In mosquitoes, existing infection with Plasmodium facilitates the establishment of a second infection, although the asynchronicity of gamete production subsequently prevents mating. In the trypanosome/tsetse system, flies become increasingly refractory to infection as they age, so the likelihood of a fly acquiring a second infection also decreases. This effectively restricts opportunities for trypanosome mating to co-infections picked up by the fly on its first feed, unless an existing infection increases the chance of successful second infection as in the Plasmodium/mosquito system. Using green and red fluorescent trypanosomes, we compared the rates of trypanosome infection and hybrid production in flies co-infected on the first feed, co-infected on a subsequent feed 18 days after emergence, or fed sequentially with each trypanosome clone 18 days apart. Infection rates were highest in the midguts and salivary glands (SG) of flies that received both trypanosome clones in their first feed, and were halved when the infected feed was delayed to day 18. In flies fed the two trypanosome clones sequentially, the second clone often failed to establish a midgut infection and consequently was not present in the SG. Nevertheless, hybrids were recovered from all three groups of infected flies. Meiotic stages and gametes were produced continuously from day 11 to 42 after the infective feed, and in sequentially infected flies, the co-occurrence of gametes led to hybrid formation. We found that a second trypanosome strain can establish infection in the tsetse SG 18 days after the first infected feed, with co-mingling of gametes and production of trypanosome hybrids

Expression and putative function of fibronectin and its receptor (integrin alpha(5)beta(1)) in male and female gametes during bovine fertilization in vitro.

PubMed

Thys, Mirjan; Nauwynck, Hans; Maes, Dominiek; Hoogewijs, Maarten; Vercauteren, Dries; Rijsselaere, Tom; Favoreel, Herman; Van Soom, Ann

2009-09-01

Fibronectin (Fn) is a 440 kDa glycoprotein assumed to participate in sperm-egg interaction in human. Recently, it has been demonstrated that Fn--when present during bovine IVF--strongly inhibits sperm penetration. The present study was conducted firstly to evaluate the expression of Fn and its integrin receptor (alpha(5)beta(1)) on male and female bovine gametes using indirect immunofluorescence and secondly, to determine the function of Fn during bovine IVF. Endogenous Fn was detected underneath the zona pellucida (ZP) and integrin alpha(5) on the oolemma of cumulus-denuded oocytes. Bovine spermatozoa displayed integrin alpha(5) at their equatorial segment after acrosome reaction. We established that the main inhibitory effect of exogenously supplemented Fn was located at the sperm-oolemma binding, with a (concurrent) effect on fusion, and this can probably be attributed to the binding of Fn to spermatozoa at the equatorial segment, as shown by means of Alexa Fluor 488-conjugated Fn. Combining these results, the inhibitory effect of exogenously supplemented Fn seemed to be exerted on the male gamete by binding to the exposed integrin alpha(5)beta(1) receptor after acrosome reaction. The presence of endogenous Fn underneath the ZP together with integrin alpha(5) expression on oolemma and acrosome-reacted (AR) sperm cell surface suggests a 'velcro' interaction between the endogenous Fn ligand and corresponding receptors on both (AR) sperm cell and oolemma, initiating sperm-egg binding.

Procuring gametes for research and therapy: the argument for unisex altruism--a response to Donald Evans.

PubMed Central

Dickenson, D L

1997-01-01

There has been a troublesome anomaly in the UK between cash payment to men for sperm donation and the effective assumption that women will pay to donate eggs. Some commentators, including Donald Evans in this journal, have argued that the anomaly should be resolved by treating women on the same terms as men. But this argument ignores important difficulties about property in the body, particularly in relation to gametes. There are good reasons for thinking that the contract model and payment for gametes are both inappropriate, and that a model based on altruism should be applied to both sexes. PMID:9134489

Incest, gamete donation by siblings and the importance of the genetic link.

PubMed

Pennings, G

2002-01-01

Recently, several requests have emerged in which women wished to be impregnated with donor eggs fertilized with spermatozoa of their brother. An important argument advanced against such applications is that it is a kind of incest. Four definitions of incest are reviewed in this article to evaluate the acceptability of these demands. The first three (sexual intercourse, reproduction with gametes of first-degree relatives and symbolic incest) do not apply to the cases. However, when the sister and her brother intend to raise the child as social mother and father, these requests should be considered as "intentional incest". If the brother only functions as an uncle, the request of the woman resembles the currently accepted practice of oocyte donation from sister to sister. In that case, the wish to receive gametes from a first-degree relative is motivated by the wish to establish as far as possible a genetic link with the child.

Is vitronectin the velcro that binds the gametes together?

PubMed

Fusi, F M; Bernocchi, N; Ferrari, A; Bronson, R A

1996-11-01

Evidence has been presented that the adhesion of human spermatozoa to the oolemma is mediated by integrins recognizing the Arg-Gly-Asp sequence (RGD). Fibronectin and vitronectin, glycoproteins that contain functional RGD sequences, are both present on human spermatozoa, and integrins that recognize these ligands have been detected on spermatozoa and eggs. In this work, we studied the effects of oligopeptides specifically designed to block fibronectin or vitronectin receptors on the interaction of human spermatozoa with zona-free hamster oocytes. GRGDdSP, a peptide blocking cell attachment to fibronectin, was without effect, while GdRGDSP, which blocks both fibronectin and vitronectin receptors, significantly inhibited the binding of human spermatozoa to the oolemma of zona-free hamster eggs, in a concentration-dependent manner, over a range 1-100 microM. As these experiments suggested that a vitronectin receptor plays a role in sperm-oolemmal adhesion, we performed a series of experiments studying the effects of exogenous vitronectin, when added to spermatozoa and oocytes, on gamete interactions. Sperm-oolemmal adherence, as well as sperm aggregation, was promoted by vitronectin, over range of 2.2 nM to 1 microM, but only in the presence of calcium ions. We propose that vitronectin released during the sperm acrosome reaction is recognized by both gametes and plays a role in their adhesion.

Two-generation analysis of pollen flow across a landscape. I. Male gamete heterogeneity among females.

PubMed

Smouse, P E; Dyer, R J; Westfall, R D; Sork, V L

2001-02-01

Gene flow is a key factor in the spatial genetic structure in spatially distributed species. Evolutionary biologists interested in microevolutionary processess and conservation biologists interested in the impact of landscape change require a method that measures the real time process of gene movement. We present a novel two-generation (parent-offspring) approach to the study of genetic structure (TwoGener) that allows us to quantify heterogeneity among the male gamete pools sampled by maternal trees scattered across the landscape and to estimate mean pollination distance and effective neighborhood size. First, we describe the model's elements: genetic distance matrices to estimate intergametic distances, molecular analysis of variance to determine whether pollen profiles differ among mothers, and optimal sampling considerations. Second, we evaluate the model's effectiveness by simulating spatially distributed populations. Spatial heterogeneity in male gametes can be estimated by phiFT, a male gametic analogue of Wright's F(ST) and an inverse function of mean pollination distance. We illustrate TwoGener in cases where the male gamete can be categorically or ambiguously determined. This approach does not require the high level of genetic resolution needed by parentage analysis, but the ambiguous case is vulnerable to bias in the absence of adequate genetic resolution. Finally, we apply TwoGener to an empirical study of Quercus alba in Missouri Ozark forests. We find that phiFT = 0.06, translating into about eight effective pollen donors per female and an effective pollination neighborhood as a circle of radius about 17 m. Effective pollen movement in Q. alba is more restricted than previously realized, even though pollen is capable of moving large distances. This case study illustrates that, with a modest investment in field survey and laboratory analysis, the TwoGener approach permits inferences about landscape-level gene movements.

[COMPARATIVE STUDY ON THE SECRET OF THE DONOR'S IDENTITY OF DONATED GAMETES].

PubMed

Tisseyre, Sandrine

2015-07-01

French law lies down a principle of anonymity of donated gametes. This principle is ignored by English law. Moreover, English law has established, few years ago, the contrary principle: the one of transparency of the donor's identity. This study of English law reports this evolution and its consequences.

Peering beneath the surface: novel imaging techniques to noninvasively select gametes and embryos for ART.

PubMed

Jasensky, Joshua; Swain, Jason E

2013-10-01

Embryo imaging has long been a critical tool for in vitro fertilization laboratories, aiding in morphological assessment of embryos, which remains the primary tool for embryo selection. With the recent emergence of clinically applicable real-time imaging systems to assess embryo morphokinetics, a renewed interest has emerged regarding noninvasive methods to assess gamete and embryo development as a means of inferring quality. Several studies exist that utilize novel imaging techniques to visualize or quantify intracellular components of gametes and embryos with the intent of correlating localization of organelles or molecular constitution with quality or outcome. However, the safety of these approaches varies due to the potential detrimental impact of light exposure or other variables. Along with complexity of equipment and cost, these drawbacks currently limit clinical application of these novel microscopes and imaging techniques. However, as evidenced by clinical incorporation of some real-time imaging devices as well as use of polarized microscopy, some of these imaging approaches may prove to be useful. This review summarizes the existing literature on novel imaging approaches utilized to examine gametes and embryos. Refinement of some of these imaging systems may permit clinical application and serve as a means to offer new, noninvasive selection tools to improve outcomes for various assisted reproductive technology procedures.

Do Gametes Woo? Evidence for Their Nonrandom Union at Fertilization.

PubMed

Nadeau, Joseph H

2017-10-01

A fundamental tenet of inheritance in sexually reproducing organisms such as humans and laboratory mice is that gametes combine randomly at fertilization, thereby ensuring a balanced and statistically predictable representation of inherited variants in each generation. This principle is encapsulated in Mendel's First Law. But exceptions are known. With transmission ratio distortion, particular alleles are preferentially transmitted to offspring. Preferential transmission usually occurs in one sex but not both, and is not known to require interactions between gametes at fertilization. A reanalysis of our published work in mice and of data in other published reports revealed instances where any of 12 mutant genes biases fertilization, with either too many or too few heterozygotes and homozygotes, depending on the mutant gene and on dietary conditions. Although such deviations are usually attributed to embryonic lethality of the underrepresented genotypes, the evidence is more consistent with genetically-determined preferences for specific combinations of egg and sperm at fertilization that result in genotype bias without embryo loss. This unexpected discovery of genetically-biased fertilization could yield insights about the molecular and cellular interactions between sperm and egg at fertilization, with implications for our understanding of inheritance, reproduction, population genetics, and medical genetics. Copyright © 2017 by the Genetics Society of America.

Does selection for gamete dispersal and capture lead to a sex difference in clump water-holding capacity?

PubMed

Moore, Jonathan D; Kollar, Leslie M; McLetchie, D Nicholas

2016-08-01

Differences in male and female reproductive function can lead to selection for sex-specific gamete dispersal and capture traits. These traits have been explored from shoot to whole plant levels in wind-pollinated species. While shoot traits have been explored in water-fertilized species, little is known about how whole plant morphology affects gamete dispersal and capture. We used the dioecious, water-fertilized plant Bryum argenteum to test for differences in clump morphology and water-holding characteristics consistent with divergent selection. We hypothesized that sex-specific clump morphology, arising at maturity, produces relatively low male water-holding capacity for gamete dispersal and high female capacity for gamete capture. We measured isolated young shoot and clump water-holding capacity and clump morphological characteristics on greenhouse-grown plants. Young shoot capacity was used to predict clump capacity, which was compared with actual clump capacity. Young male shoots held more water per unit length, and male clumps had higher shoot density, which extrapolated to higher clump water-holding capacity. However, female clumps held more water and were taller with more robust shoots. Actual clump capacity correlated positively with clump height and shoot cross-sectional area. The sex difference in actual clump capacity and its unpredictability from younger shoots are consistent with our hypothesis that males should hold less water than females to facilitate sexual reproduction. These results provide conceptual connections to other plant groups and implications for connecting divergent selection to female-biased sex ratios in B. argenteum and other bryophytes. © 2016 Botanical Society of America.

Characterization of fusion genes and the significantly expressed fusion isoforms in breast cancer by hybrid sequencing

PubMed Central

Weirather, Jason L.; Afshar, Pegah Tootoonchi; Clark, Tyson A.; Tseng, Elizabeth; Powers, Linda S.; Underwood, Jason G.; Zabner, Joseph; Korlach, Jonas; Wong, Wing Hung; Au, Kin Fai

2015-01-01

We developed an innovative hybrid sequencing approach, IDP-fusion, to detect fusion genes, determine fusion sites and identify and quantify fusion isoforms. IDP-fusion is the first method to study gene fusion events by integrating Third Generation Sequencing long reads and Second Generation Sequencing short reads. We applied IDP-fusion to PacBio data and Illumina data from the MCF-7 breast cancer cells. Compared with the existing tools, IDP-fusion detects fusion genes at higher precision and a very low false positive rate. The results show that IDP-fusion will be useful for unraveling the complexity of multiple fusion splices and fusion isoforms within tumorigenesis-relevant fusion genes. PMID:26040699

Epigenetic effects of methoxychlor and vinclozolin on male gametes.

PubMed

Paoloni-Giacobino, Ariane

2014-01-01

Imprinting is an epigenetic form of gene regulation that mediates a parent-of-origin-dependent expression of the alleles of a number of genes. Imprinting, which occurs at specific sites within or surrounding the gene, called differentially methylated domains, consists in a methylation of CpGs. The appropriate transmission of genomics imprints is essential for the control of embryonic development and fetal growth. A number of endocrine disruptors (EDs) affect male reproductive tract development and spermatogenesis. It was postulated that the genetic effects of EDs might be induced by alterations in gene imprinting. We tested two EDs: methoxychlor and vinclozolin. Their administration during gestation induced in the offspring a decrease in sperm counts and significant modifications in the methylation pattern of a selection of paternally and maternally expressed canonical imprinted genes. The observation that imprinting was largely untouched in somatic cells suggests that EDs exert their damaging effects via the process of reprogramming that is unique to gamete development. Interestingly, the effects were transgenerational, although disappearing gradually from F1 to F3. A systematic analysis showed a heterogeneity in the CpG sensitivity to EDs. We propose that the deleterious effects of EDs on the male reproductive system are mediated by imprinting defects in the sperm. The reported effects of EDs on human male spermatogenesis might be mediated by analogous imprinting alterations. © 2014 Elsevier Inc. All rights reserved.

Participation of cysteine-rich secretory proteins (CRISP) in mammalian sperm-egg interaction.

PubMed

Cohen, Débora J; Busso, Dolores; Da Ros, Vanina; Ellerman, Diego A; Maldera, Julieta A; Goldweic, Nadia; Cuasnicu, Patricia S

2008-01-01

Mammalian fertilization is a complex multi-step process mediated by different molecules present on both gametes. CRISP1 (cysteine-rich secretory protein 1) is an epididymal protein thought to participate in gamete fusion through its binding to egg-complementary sites. Structure-function studies using recombinant fragments of CRISP1 as well as synthetic peptides reveal that its egg-binding ability resides in a 12 amino acid region corresponding to an evolutionary conserved motif of the CRISP family, named Signature 2 (S2). Further experiments analyzing both the ability of other CRISP proteins to bind to the rat egg and the amino acid sequence of their S2 regions show that the amino acid sequence of the S2 is needed for CRISP1 to interact with the egg. CRISP1 appears to be involved in the first step of sperm binding to the zona pellucida, identifying a novel role for this protein in fertilization. The observation that sperm testicular CRISP2 is also able to bind to the egg surface suggests a role for this protein in gamete fusion. Subsequent experiments confirmed the participation of CRISP2 in this step of fertilization and revealed that CRISP1 and CRISP2 interact with common egg surface binding sites. Together, these results suggest a functional cooperation between CRISP1 and CRISP2 to ensure the success of fertilization. These observations contribute to a better understanding of the molecular mechanisms underlying mammalian fertilization.

Noninvasive imaging systems for gametes and embryo selection in IVF programs: a review.

PubMed

Omidi, Marjan; Faramarzi, Azita; Agharahimi, Azam; Khalili, Mohammad Ali

2017-09-01

Optimizing the efficiency of the in vitro fertilization procedure by improving pregnancy rates and reducing the risks of multiple pregnancies simultaneously are the primary goals of the current assisted reproductive technology program. With the move to single embryo transfers, the need for more cost-effective and noninvasive methods for embryo selection prior to transfer is paramount. These aims require advancement in a more acquire gametes/embryo testing and selection procedures using high-tech devices. Therefore, the aim of the present review is to evaluate the efficacy of noninvasive imaging systems in the current literatures, focusing on the potential clinical application in infertile patients undergoing assisted reproductive technology treatments. In this regards, three advanced imaging systems of motile sperm organelle morphology examination, polarization microscopy and time-lapse monitoring for the best selection of the gametes and preimplantation embryos are introduced in full. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Mandatory counseling for gamete donation recipients: ethical dilemmas.

PubMed

Benward, Jean

2015-09-01

Mental health professionals have engaged in mandatory pretreatment counseling and assessment of patients seeking treatment at IVF programs in the United States since the 1980s. At present, most recipient patients undergoing IVF with egg or embryo donation in the United States are required to meet with a mental health professional for one pretreatment session. Mandatory counseling of gamete recipients is fraught with ethical questions for the mental health professional. Attention to issues of autonomy, confidentiality, role clarity, along with self-evaluation and openness with the patient can help lessen the impact of these ethical challenges. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Evaluation of fusion protein cleavage site sequences of Newcastle disease virus in genotype matched vaccines.

PubMed

Kim, Shin-Hee; Chen, Zongyan; Yoshida, Asuka; Paldurai, Anandan; Xiao, Sa; Samal, Siba K

2017-01-01

Newcastle disease virus (NDV) causes a devastating poultry disease worldwide. Frequent outbreaks of NDV in chickens vaccinated with conventional live vaccines suggest a need to develop new vaccines that are genetically matched against circulating NDV strains, such as the genotype V virulent strains currently circulating in Mexico and Central America. In this study, a reverse genetics system was developed for the virulent NDV strain Mexico/01/10 strain and used to generate highly attenuated vaccine candidates by individually modifying the cleavage site sequence of fusion (F) protein. The cleavage site sequence of parental virus was individually changed to those of the avirulent NDV strain LaSota and other serotypes of avian paramyxoviruses (APMV serotype-2, -3, -4, -6, -7, -8, and -9). In general, these mutations affected cell-to-cell fusion activity in vitro and the efficiency of the F protein cleavage and made recombinant Mexico/01/10 (rMex) virus highly attenuated in chickens. When chickens were immunized with the rMex mutant viruses and challenged with the virulent parent virus, there was reduced challenge virus shedding compared to birds immunized with the heterologous vaccine strain LaSota. Among the vaccine candidates, rMex containing the cleavage site sequence of APMV-2 induced the highest neutralizing antibody titer and completely protected chickens from challenge virus shedding. These results show the role of the F protein cleavage site sequence of each APMV type in generating genotype V-matched vaccines and the efficacy of matched vaccine strains to provide better protection against NDV strains currently circulating in Mexico.

Mammalian diversity: gametes, embryos and reproduction.

PubMed

Behringer, Richard R; Eakin, Guy S; Renfree, Marilyn B

2006-01-01

The class Mammalia is composed of approximately 4800 extant species. These mammalian species are divided into three subclasses that include the monotremes, marsupials and eutherians. Monotremes are remarkable because these mammals are born from eggs laid outside of the mother's body. Marsupial mammals have relatively short gestation periods and give birth to highly altricial young that continue a significant amount of 'fetal' development after birth, supported by a highly sophisticated lactation. Less than 10% of mammalian species are monotremes or marsupials, so the great majority of mammals are grouped into the subclass Eutheria, including mouse and human. Mammals exhibit great variety in morphology, physiology and reproduction. In the present article, we highlight some of this remarkable diversity relative to the mouse, one of the most widely used mammalian model organisms, and human. This diversity creates challenges and opportunities for gamete and embryo collection, culture and transfer technologies.

"I am Your Mother and Your Father!" In Vitro Derived Gametes and the Ethics of Solo Reproduction.

PubMed

Cutas, Daniela; Smajdor, Anna

2017-12-01

In this paper, we will discuss the prospect of human reproduction achieved with gametes originating from only one person. According to statements by a minority of scientists working on the generation of gametes in vitro, it may become possible to create eggs from men's non-reproductive cells and sperm from women's. This would enable, at least in principle, the creation of an embryo from cells obtained from only one individual: 'solo reproduction'. We will consider what might motivate people to reproduce in this way, and the implications that solo reproduction might have for ethics and policy. We suggest that such an innovation is unlikely to revolutionise reproduction and parenting. Indeed, in some respects it is less revolutionary than in vitro fertilisation as a whole. Furthermore, we show that solo reproduction with in vitro created gametes is not necessarily any more ethically problematic than gamete donation-and probably less so. Where appropriate, we draw parallels with the debate surrounding reproductive cloning. We note that solo reproduction may serve to perpetuate reductive geneticised accounts of reproduction, and that this may indeed be ethically questionable. However, in this it is not unique among other technologies of assisted reproduction, many of which focus on genetic transmission. It is for this reason that a ban on solo reproduction might be inconsistent with continuing to permit other kinds of reproduction that also bear the potential to strengthen attachment to a geneticised account of reproduction. Our claim is that there are at least as good reasons to pursue research towards enabling solo reproduction, and eventually to introduce solo reproduction as an option for fertility treatment, as there are to do so for other infertility related purposes.

Isolation and in vitro binding of mating type plus fertilization tubules from Chlamydomonas.

PubMed

Wilson, Nedra F

2008-01-01

During fertilization in Chlamydomonas, adhesion and fusion of gametes occur at the tip of specialized regions of the plasma membrane, known as mating structures. The mating type minus (mt[-]) structure is a slightly raised dome-shaped region located at the apical end of the cell body. In contrast, the activated mating type plus (mt[+]) structure is an actin-filled, microvillouslike organelle. Interestingly, a similar type of "fusion organelle" is conserved across diverse groups. Chlamydomonas provides an ideal model system for studying the process of gametic cell fusion in that it is amenable to genetic manipulations as well as cell and molecular biological approaches. Moreover, the ease of culturing Chlamydomonas combined with the ability to isolate the mt(+) fertilization tubule and the development of in vitro assays for adhesion makes it an ideal system for biochemical studies focused on dissecting the molecular mechanisms that underlie the complex process of gametic cell fusion.

Characterization of fusion genes and the significantly expressed fusion isoforms in breast cancer by hybrid sequencing.

PubMed

Weirather, Jason L; Afshar, Pegah Tootoonchi; Clark, Tyson A; Tseng, Elizabeth; Powers, Linda S; Underwood, Jason G; Zabner, Joseph; Korlach, Jonas; Wong, Wing Hung; Au, Kin Fai

2015-10-15

We developed an innovative hybrid sequencing approach, IDP-fusion, to detect fusion genes, determine fusion sites and identify and quantify fusion isoforms. IDP-fusion is the first method to study gene fusion events by integrating Third Generation Sequencing long reads and Second Generation Sequencing short reads. We applied IDP-fusion to PacBio data and Illumina data from the MCF-7 breast cancer cells. Compared with the existing tools, IDP-fusion detects fusion genes at higher precision and a very low false positive rate. The results show that IDP-fusion will be useful for unraveling the complexity of multiple fusion splices and fusion isoforms within tumorigenesis-relevant fusion genes. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Regulatory considerations for global transfer of cryopreserved fish gametes

USGS Publications Warehouse

Jenkins, Jill A.; Tiersch, Terrence R.; Green, Christopher C.

2011-01-01

Federal and state resource managers, scientists, lawmakers, business and development investors, and the general public all struggle with issues surrounding the conservation of our biological heritage, especially in the face of increased population growth and consequent anthropogenic disturbances. Conservation interests include recovering exploited aquatic populations, decreasing the loss of genetic diversity, and reintroducing locally depleted species. However, research on husbandry and other techniques critical to implementing conservation strategies is often not started until few individuals remain. A program in the cryopreservation of gametes and embryos from aquatic species would address several of these conservation concerns by allowing the establishment of gene banks

Consecutive five-year analysis of paternal and maternal gene flow and contributions of gametic heterogeneities to overall genetic composition of dispersed seeds of Pinus densiflora (Pinaceae).

PubMed

Iwaizumi, Masakazu G; Takahashi, Makoto; Isoda, Keiya; Austerlitz, Frédéric

2013-09-01

Genetic variability in monoecious woody plant populations results from the assemblage of individuals issued from asymmetrical male and female reproductive functions, produced during spatially and temporarily heterogeneous reproductive and dispersal events. Here we investigated the dispersal patterns and levels of genetic diversity and differentiation of both paternal and maternal gametes in a natural population of Pinus densiflora at the multiple-year scale as long as five consecutive years. • We analyzed the paternity and maternity for 1576 seeds and 454 candidate adult trees using nuclear DNA polymorphisms of diploid biparental embryos and haploid maternal megagametophytes at eight microsatellite loci. • Despite the low levels of genetic differentiation among gamete groups, a two-way AMOVA analysis showed that the parental origin (paternal vs. maternal gametes), the year of gamete production and their interaction had significant effects on the genetic composition of the seeds. While maternal gamete groups showed a significant FST value across the 5 years, this was not true for their paternal counterparts. Within the population, we found that the relative reproductive contributions of the paternal vs. the maternal parent differed among adult trees, the maternal contributions showing a larger year-to-year fluctuation. • The overall genetic variability of dispersed seeds appeared to result from two sources of heterogeneity: the difference between paternal and maternal patterns of reproduction and gamete dispersal and year-to-year heterogeneity of reproduction of adult trees, especially in their maternal reproduction.

Polyploidization mechanisms: temperature environment can induce diploid gamete formation in Rosa sp.

PubMed

Pécrix, Yann; Rallo, Géraldine; Folzer, Hélène; Cigna, Mireille; Gudin, Serge; Le Bris, Manuel

2011-06-01

Polyploidy is an important evolutionary phenomenon but the mechanisms by which polyploidy arises still remain underexplored. There may be an environmental component to polyploidization. This study aimed to clarify how temperature may promote diploid gamete formation considered an essential element for sexual polyploidization. First of all, a detailed cytological analysis of microsporogenesis and microgametogenesis was performed to target precisely the key developmental stages which are the most sensitive to temperature. Then, heat-induced modifications in sporad and pollen characteristics were analysed through an exposition of high temperature gradient. Rosa plants are sensitive to high temperatures with a developmental sensitivity window limited to meiosis. Moreover, the range of efficient temperatures is actually narrow. 36 °C at early meiosis led to a decrease in pollen viability, pollen ectexine defects but especially the appearance of numerous diploid pollen grains. They resulted from dyads or triads mainly formed following heat-induced spindle misorientations in telophase II. A high temperature environment has the potential to increase gamete ploidy level. The high frequencies of diplogametes obtained at some extreme temperatures support the hypothesis that polyploidization events could have occurred in adverse conditions and suggest polyploidization facilitating in a global change context.

Influences of DMP on the Fertilization Process and Subsequent Embryogenesis of Abalone (Haliotis diversicolor supertexta) by Gametes Exposure

PubMed Central

Cai, Zhong-Hua

2011-01-01

Di-methyl phthalate (DMP), a typical endocrine disrupting chemical (EDC), is ubiquitously distributed in aquatic environments; yet studies regarding its impact on gametes and the resulting effects on embryogenesis in marine gastropods are relatively scarce. In this study, the influences of DMP on the gametes and subsequent developmental process of abalone (Haliotis diversicolor supertexta, a representative marine benthic gastropod) were assessed. Newborn abalone eggs and sperm were exposed separately to different DMP concentrations (1, 10 or 100 ppb) for 60 min. At the end-point of exposure, the DMP-treated eggs and sperm were collected for analysis of their ultra-structures, ATPase activities and total lipid levels, and the fertilized gametes (embryos) were collected to monitor related reproductive parameters (fertilization rate, abnormal development rate and hatching success rate). Treatment with DMP did not significantly alter the structure or total lipid content of eggs at any of the doses tested. Hatching failures and morphological abnormalities were only observed with the highest dose of DMP (100 ppb). However, DMP exposure did suppress sperm ATPase activities and affect the morphological character of their mitochondria. DMP-treated sperm exhibited dose-dependent decreases in fertilization efficiency, morphogenesis and hatchability. Relatively obvious toxicological effects were observed when both sperm and eggs were exposed to DMP. Furthermore, RT-PCR results indicate that treatment of gametes with DMP changed the expression patterns of physiologically-regulated genes (cyp3a, 17β-HSD-11 and 17β-HSD-12) in subsequent embryogenesis. Taken together, this study proofed that pre-fertilization exposure of abalone eggs, sperm or both to DMP adversely affects the fertilization process and subsequent embryogenesis. PMID:22028799

An essential role of the basal body protein SAS-6 in Plasmodium male gamete development and malaria transmission

PubMed Central

Marques, Sara R; Ramakrishnan, Chandra; Carzaniga, Raffaella; Blagborough, Andrew M; Delves, Michael J; Talman, Arthur M; Sinden, Robert E

2015-01-01

Gametocytes are the sole Plasmodium parasite stages that infect mosquitoes; therefore development of functional gametes is required for malaria transmission. Flagellum assembly of the Plasmodium male gamete differs from that of most other eukaryotes in that it is intracytoplasmic but retains a key conserved feature: axonemes assemble from basal bodies. The centriole/basal body protein SAS-6 normally regulates assembly and duplication of these organelles and its depletion causes severe flagellar/ciliary abnormalities in a diverse array of eukaryotes. Since basal body and flagellum assembly are intimately coupled to male gamete development in Plasmodium, we hypothesized that SAS-6 disruption may cause gametogenesis defects and perturb transmission. We show that Plasmodium berghei sas6 knockouts display severely abnormal male gametogenesis presenting reduced basal body numbers, axonemal assembly defects and abnormal nuclear allocation. The defects in gametogenesis reduce fertilization and render Pbsas6 knockouts less infectious to mosquitoes. Additionally, we show that lack of Pbsas6 blocks transmission from mosquito to vertebrate host, revealing an additional yet undefined role in ookinete to sporulating oocysts transition. These findings underscore the vulnerability of the basal body/SAS-6 to malaria transmission blocking interventions. PMID:25154861

Effect of fusion protein cleavage site sequence on generation of a genotype VII Newcastle disease virus vaccine.

PubMed

Manoharan, Vinoth K; Varghese, Berin P; Paldurai, Anandan; Samal, Siba K

2018-01-01

Newcastle disease (ND) causes severe economic loss to poultry industry worldwide. Frequent outbreaks of ND in commercial chickens vaccinated with live vaccines suggest a need to develop improved vaccines that are genetically matched against circulating Newcastle disease virus (NDV) strains. In this study, the fusion protein cleavage site (FPCS) sequence of NDV strain Banjarmasin/010 (Banj), a genotype VII NDV, was individually modified using primer mutagenesis to those of avian paramyxovirus (APMV) serotypes 2, 7 and 8 and compared with the recombinant Banjarmasin (rBanj) with avirulent NDV LaSota cleavage site (rBanj-LaSota). These FPCS mutations changed the in vitro cell-to-cell fusion activity and made rBanj FPCS mutant viruses highly attenuated in chickens. When chickens immunized with the rBanj FPCS mutant viruses and challenged with the virulent Banj, there was reduced challenge virus shedding observed compared to chickens immunized with the heterologous vaccine strain LaSota. Among the genotype VII NDV Banj vaccine candidates, rBanj-LaSota and rBanj containing FPCS of APMV-8 induced highest neutralizing antibody titers and protected chickens with reduced challenge virus shedding. These results show the effect of the F protein cleavage site sequence in generating genotype VII matched NDV vaccines.

Gamete donors' expectations and experiences of contact with their donor offspring

PubMed Central

Kirkman, Maggie; Bourne, Kate; Fisher, Jane; Johnson, Louise; Hammarberg, Karin

2014-01-01

STUDY QUESTION What are the expectations and experiences of anonymous gamete donors about contact with their donor offspring? SUMMARY ANSWER Rather than consistently wanting to remain distant from their donor offspring, donors' expectations and experiences of contact with donor offspring ranged from none to a close personal relationship. WHAT IS KNOWN ALREADY Donor conception is part of assisted reproduction in many countries, but little is known about its continuing influence on gamete donors' lives. STUDY DESIGN, SIZE, DURATION A qualitative research model appropriate for understanding participants' views was employed; semi-structured interviews were conducted during January–March 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS Before 1998, gamete donors in Victoria, Australia, were subject to evolving legislation that allowed them to remain anonymous or (from 1988) to consent to the release of identifying information. An opportunity to increase knowledge of donors' expectations and experiences of contact with their donor offspring recently arose in Victoria when a recommendation was made to introduce mandatory identification of donors on request from their donor offspring, with retrospective effect. Pre-1998 donors were invited through an advertising campaign to be interviewed about their views, experiences and expectations; 36 sperm donors and 6 egg donors participated. MAIN RESULTS AND THE ROLE OF CHANCE This research is unusual in achieving participation by donors who would not normally identify themselves to researchers or government inquiries. Qualitative thematic analysis revealed that most donors did not characterize themselves as parents of their donor offspring. Donors' expectations and experiences of contact with donor offspring ranged from none to a close personal relationship. LIMITATIONS, REASONS FOR CAUTION It is not possible to establish whether participants were representative of all pre-1998 donors. WIDER IMPLICATIONS OF THE FINDINGS Anonymous

Salmonid Gamete Preservation in the Snake River Basin, 2001 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Robyn; Kucera, Paul

2002-06-01

Steelhead (Oncorhynchus mykiss) and chinook salmon (Oncorhynchus tshawytscha) populations in the Northwest are decreasing. Genetic diversity is being lost at an alarming rate. Along with reduced population and genetic variability, the loss of biodiversity means a diminished environmental adaptability. The Nez Perce Tribe (Tribe) strives to ensure availability of genetic samples of the existing male salmonid population by establishing and maintaining a germplasm repository. The sampling strategy, initiated in 1992, has been to collect and preserve male salmon and steelhead genetic diversity across the geographic landscape by sampling within the major river subbasins in the Snake River basin, assuming amore » metapopulation structure existed historically. Gamete cryopreservation conserves genetic diversity in a germplasm repository, but is not a recovery action for listed fish species. The Tribe was funded in 2001 by the Bonneville Power Administration (BPA) and the U.S. Fish and Wildlife Service Lower Snake River Compensation Plan (LSRCP) to coordinate gene banking of male gametes from Endangered Species Act (ESA) listed steelhead and spring and summer chinook salmon in the Snake River basin. In 2001, a total of 398 viable chinook salmon semen samples from the Lostine River, Catherine Creek, upper Grande Ronde River, Lookingglass Hatchery (Imnaha River stock), Lake Creek, the South Fork Salmon River weir, Johnson Creek, Big Creek, Capehorn Creek, Marsh Creek, Pahsimeroi Hatchery, and Sawtooth Hatchery (upper Salmon River stock) were cryopreserved. Also, 295 samples of male steelhead gametes from Dworshak Hatchery, Fish Creek, Grande Ronde River, Little Sheep Creek, Pahsimeroi Hatchery and Oxbow Hatchery were also cryopreserved. The Grande Ronde chinook salmon captive broodstock program stores 680 cryopreserved samples at the University of Idaho as a long-term archive, half of the total samples. A total of 3,206 cryopreserved samples from Snake River basin

Ethical aspects of creating human-nonhuman chimeras capable of human gamete production and human pregnancy.

PubMed

Palacios-González, César

2015-01-01

In this paper I explore some of the moral issues that could emerge from the creation of human-nonhuman chimeras (HNH-chimeras) capable of human gamete production and human pregnancy. First I explore whether there is a cogent argument against the creation of HNH-chimeras that could produce human gametes. I conclude that so far there is none, and that in fact there is at least one good moral reason for producing such types of creatures. Afterwards I explore some of the moral problems that could emerge from the fact that a HNH-chimera could become pregnant with a human conceptus. I focus on two sets of problems: problems that would arise by virtue of the fact that a human is gestated by a nonhuman creature, and problems that would emerge from the fact that such pregnancies could affect the health of the HNH-chimera.

Avian paramyxovirus serotype 1 strains of low virulence with unusual fusion protein cleavage sites isolated from poultry species

USDA-ARS?s Scientific Manuscript database

Avian paramyxo-serotype-1 viruses (APMV1) with fusion cleavage sites containing two basic amino acids and a phenylalanine (F) at position 117 have been isolated from poultry species in two states from 2007-2009. The intracerebral pathogenicity indices for these viruses are of low virulence at 0.00 ...

Probabilistic evaluation of seismic isolation effect with respect to siting of a fusion reactor facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeda, Masatoshi; Komura, Toshiyuki; Hirotani, Tsutomu

1995-12-01

Annual failure probabilities of buildings and equipment were roughly evaluated for two fusion-reactor-like buildings, with and without seismic base isolation, in order to examine the effectiveness of the base isolation system regarding siting issues. The probabilities are calculated considering nonlinearity and rupture of isolators. While the probability of building failure for both buildings on the same site was almost equal, the function failures for equipment showed that the base-isolated building had higher reliability than the non-isolated building. Even if the base-isolated building alone is located on a higher seismic hazard area, it could compete favorably with the ordinary one inmore » reliability of equipment.« less

A camel-derived MERS-CoV with a variant spike protein cleavage site and distinct fusion activation properties

PubMed Central

Millet, Jean Kaoru; Goldstein, Monty E; Labitt, Rachael N; Hsu, Hung-Lun; Daniel, Susan; Whittaker, Gary R

2016-01-01

Middle East respiratory syndrome coronavirus (MERS-CoV) continues to circulate in both humans and camels, and the origin and evolution of the virus remain unclear. Here we characterize the spike protein of a camel-derived MERS-CoV (NRCE-HKU205) identified in 2013, early in the MERS outbreak. NRCE-HKU205 spike protein has a variant cleavage motif with regard to the S2′ fusion activation site—notably, a novel substitution of isoleucine for the otherwise invariant serine at the critical P1′ cleavage site position. The substitutions resulted in a loss of furin-mediated cleavage, as shown by fluorogenic peptide cleavage and western blot assays. Cell–cell fusion and pseudotyped virus infectivity assays demonstrated that the S2′ substitutions decreased spike-mediated fusion and viral entry. However, cathepsin and trypsin-like protease activation were retained, albeit with much reduced efficiency compared with the prototypical EMC/2012 human strain. We show that NRCE-HKU205 has more limited fusion activation properties possibly resulting in more restricted viral tropism and may represent an intermediate in the complex pattern of MERS-CoV ecology and evolution. PMID:27999426

Genetic mapping of centromeres in the nine Citrus clementina chromosomes using half-tetrad analysis and recombination patterns in unreduced and haploid gametes.

PubMed

Aleza, Pablo; Cuenca, José; Hernández, María; Juárez, José; Navarro, Luis; Ollitrault, Patrick

2015-03-08

Mapping centromere locations in plant species provides essential information for the analysis of genetic structures and population dynamics. The centromere's position affects the distribution of crossovers along a chromosome and the parental heterozygosity restitution by 2n gametes is a direct function of the genetic distance to the centromere. Sexual polyploidisation is relatively frequent in Citrus species and is widely used to develop new seedless triploid cultivars. The study's objectives were to (i) map the positions of the centromeres of the nine Citrus clementina chromosomes; (ii) analyse the crossover interference in unreduced gametes; and (iii) establish the pattern of genetic recombination in haploid clementine gametes along each chromosome and its relationship with the centromere location and distribution of genic sequences. Triploid progenies were derived from unreduced megagametophytes produced by second-division restitution. Centromere positions were mapped genetically for all linkage groups using half-tetrad analysis. Inference of the physical locations of centromeres revealed one acrocentric, four metacentric and four submetacentric chromosomes. Crossover interference was observed in unreduced gametes, with variation seen between chromosome arms. For haploid gametes, a strong decrease in the recombination rate occurred in centromeric and pericentromeric regions, which contained a low density of genic sequences. In chromosomes VIII and IX, these low recombination rates extended beyond the pericentromeric regions. The genomic region corresponding to a genetic distance < 5cM from a centromere represented 47% of the genome and 23% of the genic sequences. The centromere positions of the nine citrus chromosomes were genetically mapped. Their physical locations, inferred from the genetic ones, were consistent with the sequence constitution and recombination pattern along each chromosome. However, regions with low recombination rates extended beyond the

Ectocranial suture fusion in primates: pattern and phylogeny.

PubMed

Cray, James; Cooper, Gregory M; Mooney, Mark P; Siegel, Michael I

2014-03-01

Patterns of ectocranial suture fusion among Primates are subject to species-specific variation. In this study, we used Guttman Scaling to compare modal progression of ectocranial suture fusion among Hominidae (Homo, Pan, Gorilla, and Pongo), Hylobates, and Cercopithecidae (Macaca and Papio) groups. Our hypothesis is that suture fusion patterns should reflect their evolutionary relationship. For the lateral-anterior suture sites there appear to be three major patterns of fusion, one shared by Homo-Pan-Gorilla, anterior to posterior; one shared by Pongo and Hylobates, superior to inferior; and one shared by Cercopithecidae, posterior to anterior. For the vault suture pattern, the Hominidae groups reflect the known phylogeny. The data for Hylobates and Cercopithecidae groups is less clear. The vault suture site termination pattern of Papio is similar to that reported for Gorilla and Pongo. Thus, it may be that some suture sites are under larger genetic influence for patterns of fusion, while others are influenced by environmental/biomechanic influences. Copyright © 2013 Wiley Periodicals, Inc.

The ethics of anonymous gamete donation: is there a right to know one's genetic origins?

PubMed

De Melo-Martín, Inmaculada

2014-01-01

A growing number of jurisdictions hold that gamete donors must be identifiable to the children born with their eggs or sperm, on grounds that being able to know about one's genetic origins is a fundamental moral right. But the argument for that belief has not yet been adequately made.

Recent microfluidic devices for studying gamete and embryo biomechanics.

PubMed

Lai, David; Takayama, Shuichi; Smith, Gary D

2015-06-25

The technical challenges of biomechanic research such as single cell analysis at a high monetary cost, labor, and time for just a small number of measurements is a good match to the strengths of microfluidic devices. New scientific discoveries in the fertilization and embryo development process, of which biomechanics is a major subset of interest, is crucial to fuel the continual improvement of clinical practice in assisted reproduction. The following review will highlight some recent microfluidic devices tailored for gamete and embryo biomechanics where biomimicry arises as a major theme of microfluidic device design and function, and the application of fundamental biomechanic principles are used to improve outcomes of cryopreservation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Food-Nonfood Discrimination in Ancestral Vertebrates: Gamete Cannibalism and the Origin of the Adaptive Immune System.

PubMed

Corcos, D

2015-11-01

Adaptive immunity is a complex system that appeared twice in vertebrates (in gnathostomes and in jawless fish) although it is not required for invertebrate defence. The adaptive immune system is tightly associated with self-non-self discrimination, and it is now clear that this interplay is not limited to the prevention of autoreactivity. Micro-organisms are usually considered for their pathogenicity or symbiotic ability, but, for most small metazoans, they mainly constitute food. Vertebrates are characterized by feeding by predation on larger preys, when compared to their ancestors who were filter feeders and ate micro-organisms. Predation gives a strong selective advantage, not only due to the availability of new food resources but also by the ability to eliminate competitors for environmental resources (intraguild predation (IGP)). Unlike size-structured IGP, intraspecific predation of juveniles, zygotes or gametes can be detrimental for species fitness in some circumstances. The ability of individuals to recognize highly polymorphic molecules on the surface of gametes present in the plankton and so distinguish self versus non-self gametes might have constituted a strong selective advantage in intraspecific competition. Here, I propose the theory that the capacity to rearrange receptors has been selected in ancestral vertebrates as a consequence of this strong need for discriminating between hetero-cannibalism versus filial cannibalism. This evolutionary origin sheds light on presently unexplained features of the immune system, including the existence of regulatory T cells and of non-pathogenic natural autoimmunity. © 2015 The Foundation for the Scandinavian Journal of Immunology.

9 CFR 93.905 - Declaration and other documents for live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Animal Species General Provisions for Svc-Regulated Fish Species § 93.905 Declaration and other documents... entry, the name and address of the importer, the name and address of the broker, the origin of the live fish, fertilized eggs, or gametes, the number, species, and the purpose of the importation, the name of...

9 CFR 93.905 - Declaration and other documents for live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Animal Species General Provisions for Svc-Regulated Fish Species § 93.905 Declaration and other documents... entry, the name and address of the importer, the name and address of the broker, the origin of the live fish, fertilized eggs, or gametes, the number, species, and the purpose of the importation, the name of...

9 CFR 93.905 - Declaration and other documents for live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Animal Species General Provisions for Svc-Regulated Fish Species § 93.905 Declaration and other documents... entry, the name and address of the importer, the name and address of the broker, the origin of the live fish, fertilized eggs, or gametes, the number, species, and the purpose of the importation, the name of...

A single mutation results in diploid gamete formation and parthenogenesis in a Drosophila yemanuclein-alpha meiosis I defective mutant.

PubMed

Meyer, Régis E; Delaage, Michèle; Rosset, Roland; Capri, Michèle; Aït-Ahmed, Ounissa

2010-11-16

Sexual reproduction relies on two key events: formation of cells with a haploid genome (the gametes) and restoration of diploidy after fertilization. Therefore the underlying mechanisms must have been evolutionary linked and there is a need for evidence that could support such a model. We describe the identification and the characterization of yem1, the first yem-alpha mutant allele (V478E), which to some extent affects diploidy reduction and its restoration. Yem-alpha is a member of the Ubinuclein/HPC2 family of proteins that have recently been implicated in playing roles in chromatin remodeling in concert with HIRA histone chaperone. The yem1 mutant females exhibited disrupted chromosome behavior in the first meiotic division and produced very low numbers of viable progeny. Unexpectedly these progeny did not display paternal chromosome markers, suggesting that they developed from diploid gametes that underwent gynogenesis, a form of parthenogenesis that requires fertilization. We focus here on the analysis of the meiotic defects exhibited by yem1 oocytes that could account for the formation of diploid gametes. Our results suggest that yem1 affects chromosome segregation presumably by affecting kinetochores function in the first meiotic division. This work paves the way to further investigations on the evolution of the mechanisms that support sexual reproduction.

Line tension at lipid phase boundaries as driving force for HIV fusion peptide-mediated fusion

NASA Astrophysics Data System (ADS)

Yang, Sung-Tae; Kiessling, Volker; Tamm, Lukas K.

2016-04-01

Lipids and proteins are organized in cellular membranes in clusters, often called `lipid rafts'. Although raft-constituent ordered lipid domains are thought to be energetically unfavourable for membrane fusion, rafts have long been implicated in many biological fusion processes. For the case of HIV gp41-mediated membrane fusion, this apparent contradiction can be resolved by recognizing that the interfaces between ordered and disordered lipid domains are the predominant sites of fusion. Here we show that line tension at lipid domain boundaries contributes significant energy to drive gp41-fusion peptide-mediated fusion. This energy, which depends on the hydrophobic mismatch between ordered and disordered lipid domains, may contribute tens of kBT to fusion, that is, it is comparable to the energy required to form a lipid stalk intermediate. Line-active compounds such as vitamin E lower line tension in inhomogeneous membranes, thereby inhibit membrane fusion, and thus may be useful natural viral entry inhibitors.

Genetic control of gamete quality in the mouse--a tribute to Halina Krzanowska.

PubMed

Styrna, Jozefa

2008-01-01

In this article, we summarise the principal research findings of the distinguished Polish scientist, Professor Halina Krzanowska, related to the genetic control of mammalian gamete quality. During the early stages of her career, Halina Krzanowska conducted experiments on poultry and then she moved on to work on mice. All her research on gamete quality was conducted on the research models, consomic, congenic and recombinant inbred strains, which Krzanowska developed herself. These models differed mostly in their fertility. Krzanowska was one of the first researchers to demonstrate the influence of chromosome Y on the morphology of mice spermatozoa. She also showed that the uterotubal junction is in vivo a selection barrier for the morphologically abnormal spermatozoa, whereas in vitro abnormal spermatozoa are able to participate in fertilization, the function of selective barrier being performed by the granulosa cell layer and the zona pellucida. Another model which Krzanowska produced were chimaeras, which she used to find out if the percentage of abnormal spermatozoa and the efficiency of fertilization are determined by germ cells themselves or by environmental factors and she discovered that sperm head shape, the proportion of abnormal sperm and fertilizing capacity are determined mainly by the genotype of germ cells and only minimally by environmental factors.

Human DAZL, DAZ and BOULE genes modulate primordial germ cell and haploid gamete formation

PubMed Central

Kee, Kehkooi; Angeles, Vanessa T; Flores, Martha; Nguyen, Ha Nam; Pera, Renee A Reijo

2009-01-01

The leading cause of infertility in men and women is quantitative and qualitative defects in human germ cell (oocyte and sperm) development. Yet, it has not been possible to examine the unique developmental genetics of human germ cell formation and differentiation due to inaccessibility of germ cells during fetal development. Although several studies have shown that germ cells can be differentiated from mouse and human embryonic stem cells, human germ cells differentiated in these studies generally did not develop beyond the earliest stages1-8. Here we used a germ cell reporter to quantitate and isolate primordial germ cells derived from both male and female hESCs. Then, by silencing and overexpressing genes that encode germ cell-specific cytoplasmic RNA-binding proteins (not transcription factors), we modulated human germ cell formation and developmental progression. We observed that human DAZL (Deleted in AZoospermia-Like) functions in primordial germ cell formation, whereas closely-related genes, DAZ and BOULE, promote later stages of meiosis and development of haploid gametes. These results are significant to the generation of gametes for future basic science and potential clinical applications. PMID:19865085

Site-directed antibody immobilization using a protein A-gold binding domain fusion protein for enhanced SPR immunosensing.

PubMed

de Juan-Franco, Elena; Caruz, Antonio; Pedrajas, J R; Lechuga, Laura M

2013-04-07

We have implemented a novel strategy for the oriented immobilization of antibodies onto a gold surface based on the use of a fusion protein, the protein A-gold binding domain (PAG). PAG consists of a gold binding peptide (GBP) coupled to the immunoglobulin-binding domains of staphylococcal protein A. This fusion protein provides an easy and fast oriented immobilization of antibodies preserving its native structure, while leaving the antigen binding sites (Fab) freely exposed. Using this immobilization strategy, we have demonstrated the performance of the immunosensing of the human Growth Hormone by SPR. A limit of detection of 90 ng mL(-1) was obtained with an inter-chip variability lower than 7%. The comparison of this method with other strategies for the direct immobilization of antibodies over gold surfaces has showed the enhanced sensitivity provided by the PAG approach.

Antigen Binding and Site-Directed Labeling of Biosilica-Immobilized Fusion Proteins Expressed in Diatoms.

PubMed

Ford, Nicole R; Hecht, Karen A; Hu, DeHong; Orr, Galya; Xiong, Yijia; Squier, Thomas C; Rorrer, Gregory L; Roesijadi, Guritno

2016-03-18

The diatom Thalassiosira pseudonana was genetically modified to express biosilica-targeted fusion proteins comprising either enhanced green fluorescent protein (EGFP) or single chain antibodies engineered with a tetracysteine tagging sequence. Of interest were the site-specific binding of (1) the fluorescent biarsenical probe AsCy3 and AsCy3e to the tetracysteine tagged fusion proteins and (2) high and low molecular mass antigens, the Bacillus anthracis surface layer protein EA1 or small molecule explosive trinitrotoluene (TNT), to biosilica-immobilized single chain antibodies. Analysis of biarsenical probe binding using fluorescence and structured illumination microscopy indicated differential colocalization with EGFP in nascent and mature biosilica, supporting the use of either EGFP or bound AsCy3 and AsCy3e in studying biosilica maturation. Large increases in the lifetime of a fluorescent analogue of TNT upon binding single chain antibodies provided a robust signal capable of discriminating binding to immobilized antibodies in the transformed frustule from nonspecific binding to the biosilica matrix. In conclusion, our results demonstrate an ability to engineer diatoms to create antibody-functionalized mesoporous silica able to selectively bind chemical and biological agents for the development of sensing platforms.

9 CFR 93.902 - Ports designated for the importation of live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2013 CFR

2013-01-01

... of live fish, fertilized eggs, and gametes. 93.902 Section 93.902 Animals and Animal Products ANIMAL... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Svc-Regulated Fish Species § 93.902 Ports designated for the...

9 CFR 93.902 - Ports designated for the importation of live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2012 CFR

2012-01-01

... of live fish, fertilized eggs, and gametes. 93.902 Section 93.902 Animals and Animal Products ANIMAL... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Svc-Regulated Fish Species § 93.902 Ports designated for the...

9 CFR 93.902 - Ports designated for the importation of live fish, fertilized eggs, and gametes.

Code of Federal Regulations, 2014 CFR

2014-01-01

... of live fish, fertilized eggs, and gametes. 93.902 Section 93.902 Animals and Animal Products ANIMAL... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Svc-Regulated Fish Species § 93.902 Ports designated for the...

Gametic embryogenesis and haploid technology as valuable support to plant breeding.

PubMed

Germanà, Maria Antonietta

2011-05-01

Plant breeding is focused on continuously increasing crop production to meet the needs of an ever-growing world population, improving food quality to ensure a long and healthy life and address the problems of global warming and environment pollution, together with the challenges of developing novel sources of biofuels. The breeders' search for novel genetic combinations, with which to select plants with improved traits to satisfy both farmers and consumers, is endless. About half of the dramatic increase in crop yield obtained in the second half of the last century has been achieved thanks to the results of genetic improvement, while the residual advance has been due to the enhanced management techniques (pest and disease control, fertilization, and irrigation). Biotechnologies provide powerful tools for plant breeding, and among these ones, tissue culture, particularly haploid and doubled haploid technology, can effectively help to select superior plants. In fact, haploids (Hs), which are plants with gametophytic chromosome number, and doubled haploids (DHs), which are haploids that have undergone chromosome duplication, represent a particularly attractive biotechnological method to accelerate plant breeding. Currently, haploid technology, making possible through gametic embryogenesis the single-step development of complete homozygous lines from heterozygous parents, has already had a huge impact on agricultural systems of many agronomically important crops, representing an integral part in their improvement programmes. The aim of this review was to provide some background, recent advances, and future prospective on the employment of haploid technology through gametic embryogenesis as a powerful tool to support plant breeding.

The Effect of Filamentous Turf Algal Removal on the Development of Gametes of the Coral Orbicella annularis

PubMed Central

Cetz-Navarro, Neidy P.; Carpizo-Ituarte, Eugenio J.; Espinoza-Avalos, Julio; Chee-Barragán, Guillermina

2015-01-01

Macroalgae and filamentous turf algae (FTA) are abundant on degraded coral reefs, and the reproductive responses of corals may indicate sub-lethal stress under these conditions. The percentage of gametogenic stages (PGS) and the maximum diameter of eggs (MDE; or egg size) of Orbicella annularis were used to evaluate the effect of long- (7–10 months) and short-term (2.5 months) FTA removal (treatments T1 and T2, respectively) at both the beginning (May) and the end (August) of gametogenesis. Ramets (individual lobes of a colony) surrounded by FTA (T3) or crustose coralline algae (CCA; T4) were used as controls. The removal of FTA enhanced the development of gametes (i.e., a larger and higher percentage of mature gametes (PMG)) of O. annularis for T1 vs. T3 ramets in May and T1 and T2 vs. T3 ramets in August. Similar values of PGS and MDE between gametes from T3 and T4 in both May and August were unexpected because a previous study had shown that the same ramets of T4 (with higher tissue thickness, chlorophyll a cm-2 and zooxanthellae density and lower mitotic index values) were less stressed than ramets of T3. Evaluating coral stress through reproduction can reveal more sensitive responses than other biological parameters; within reproductive metrics, PGS can be a better stress indicator than egg size. The presence of turf algae strongly impacted the development of gametes and egg size (e.g., PMG in ramets with FTA removal increased almost twofold in comparison with ramets surrounded by FTA in August), most likely exerting negative chronic effects in the long run due to the ubiquity and permanence of turf algae in the Caribbean. These algae can be considered a stressor that affects coral sexual reproduction. Although the effects of turf algae on O. annularis are apparently less severe than those of other stressors, the future of this species is uncertain because of the combined impacts of these effects, the decline of O. annularis populations and the almost

The effect of filamentous turf algal removal on the development of gametes of the coral Orbicella annularis.

PubMed

Cetz-Navarro, Neidy P; Carpizo-Ituarte, Eugenio J; Espinoza-Avalos, Julio; Chee-Barragán, Guillermina

2015-01-01

Macroalgae and filamentous turf algae (FTA) are abundant on degraded coral reefs, and the reproductive responses of corals may indicate sub-lethal stress under these conditions. The percentage of gametogenic stages (PGS) and the maximum diameter of eggs (MDE; or egg size) of Orbicella annularis were used to evaluate the effect of long- (7-10 months) and short-term (2.5 months) FTA removal (treatments T1 and T2, respectively) at both the beginning (May) and the end (August) of gametogenesis. Ramets (individual lobes of a colony) surrounded by FTA (T3) or crustose coralline algae (CCA; T4) were used as controls. The removal of FTA enhanced the development of gametes (i.e., a larger and higher percentage of mature gametes (PMG)) of O. annularis for T1 vs. T3 ramets in May and T1 and T2 vs. T3 ramets in August. Similar values of PGS and MDE between gametes from T3 and T4 in both May and August were unexpected because a previous study had shown that the same ramets of T4 (with higher tissue thickness, chlorophyll a cm-2 and zooxanthellae density and lower mitotic index values) were less stressed than ramets of T3. Evaluating coral stress through reproduction can reveal more sensitive responses than other biological parameters; within reproductive metrics, PGS can be a better stress indicator than egg size. The presence of turf algae strongly impacted the development of gametes and egg size (e.g., PMG in ramets with FTA removal increased almost twofold in comparison with ramets surrounded by FTA in August), most likely exerting negative chronic effects in the long run due to the ubiquity and permanence of turf algae in the Caribbean. These algae can be considered a stressor that affects coral sexual reproduction. Although the effects of turf algae on O. annularis are apparently less severe than those of other stressors, the future of this species is uncertain because of the combined impacts of these effects, the decline of O. annularis populations and the almost complete

A calcium influx is triggered and propagates in the zygote as a wavefront during in vitro fertilization of flowering plants.

PubMed

Antoine, A F; Faure, J E; Cordeiro, S; Dumas, C; Rougier, M; Feijó, J A

2000-09-12

In this paper, we report direct measurement of an influx of extracellular Ca(2+) induced by gamete fusion in flowering plants. This result was obtained during maize in vitro fertilization with the use of an extracellular Ca(2+)-selective vibrating probe. Ca(2+) influx recorded at the surface of isolated egg cells, with or without adhesion of a male sperm cell, was close to zero and stable over time. Gamete fusion, however, triggered a Ca(2+) influx in the vicinity of the sperm entry site with a delay of 1.8 +/- 0.6 sec. The Ca(2+) influx spread subsequently through the whole egg cell plasma membrane as a wavefront, progressing at an estimated rate of 1.13 micrometer.(-1). Once established, Ca(2+) influx intensities were sustained, monotonic and homogeneous over the whole egg cell, with an average peak influx of 14.92 pmol .cm(-2).(-1) and an average duration of 24.4 min. The wavefront spread of channel activation correlates well with the cytological modifications induced by fertilization, such as egg cell contraction, and with the cytosolic Ca(2+) ((c)[Ca(2+)]) elevation previously reported. Calcium influx was inhibited effectively by gadolinium, possibly implicating mechanosensitive channels. Furthermore, artificial influxes created by incubation with Ca(2+) ionophores mimicked some aspects of egg activation. Taken together, these results suggest that, during fertilization in higher plants, gamete membrane fusion starts the first embryonic events by channel opening and Ca(2+) influx. In turn, (c)[Ca(2+)] may work as a trigger and possibly a space and time coordinator of many aspects of egg activation.

Post-Fusion Membrane Reorganization.

DTIC Science & Technology

1993-01-27

diphosphoglycerate , and NEM (a crosslinking agent), and ethanol treatments all had reproducible and very specific effects on the kinetic phases and the fusion product...actually, at the ultrastructure level , a double membrane multiply perforated with fusion sites (or pores). Also, because the heat treatment was within...relationships. Moreover. 2.3- Diphosphoglycerate (2-3-DPG). a naturally occuring metabolite which is known to have a regulatory role in spectrin-cytoskeletal

A single mutation results in diploid gamete formation and parthenogenesis in a Drosophila yemanuclein-alpha meiosis I defective mutant

PubMed Central

2010-01-01

Background Sexual reproduction relies on two key events: formation of cells with a haploid genome (the gametes) and restoration of diploidy after fertilization. Therefore the underlying mechanisms must have been evolutionary linked and there is a need for evidence that could support such a model. Results We describe the identification and the characterization of yem1, the first yem-alpha mutant allele (V478E), which to some extent affects diploidy reduction and its restoration. Yem-alpha is a member of the Ubinuclein/HPC2 family of proteins that have recently been implicated in playing roles in chromatin remodeling in concert with HIRA histone chaperone. The yem1 mutant females exhibited disrupted chromosome behavior in the first meiotic division and produced very low numbers of viable progeny. Unexpectedly these progeny did not display paternal chromosome markers, suggesting that they developed from diploid gametes that underwent gynogenesis, a form of parthenogenesis that requires fertilization. Conclusions We focus here on the analysis of the meiotic defects exhibited by yem1 oocytes that could account for the formation of diploid gametes. Our results suggest that yem1 affects chromosome segregation presumably by affecting kinetochores function in the first meiotic division. This work paves the way to further investigations on the evolution of the mechanisms that support sexual reproduction. PMID:21080953

Fusion Science Education Outreach

NASA Astrophysics Data System (ADS)

Danielson, C. A.; DIII-D Education Group

1996-11-01

This presentation will focus on education outreach activities at General Atomics that have been expanded to include the general population on science education with a focus on fusion energy. Outreach materials are distributed upon request both nationally and internationally. These materials include a notebook containing copies of DIII--D tour panels, fusion poster, new fusion energy video, new fusion energy brochure, and the electromagnetic spectrum curriculum. The 1996 Fusion Forum (held in the House Caucus Room) included a student/ teacher lunch with Energy Secretary Hazel O'Leary and a private visit to the Forum exhibits. The continuing partnership with Kearny High School includes lectures, job shadowing, internship, equipment donations and an award-winning electric car-racing program. Development of distribution by CD of the existing interactive fusion energy kiosk and a virtual reality tour of the DIII--D facility are underway. The DIII--D fusion education WWW site includes e-mail addresses to ``Ask the Wizard,'' and/or receive GA's outreach materials. Steve Rodecker, a local science teacher, aided by DIII--D fusion staff, won his second Tapestry Award; he also was named the ``1995 National Science Teacher of the Year'' and will be present to share his experiences with the DIII--D educational outreach program.

Antigen Binding and Site-Directed Labeling of Biosilica-Immobilized Fusion Proteins Expressed in Diatoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ford, Nicole R.; Hecht, Karen A.; Hu, Dehong

2016-01-08

The diatom Thalassiosira pseudonana was genetically modified to express biosilica-targeted fusion proteins incorporating a tetracysteine tag for site-directed labeling with biarsenical affinity probes and either EGFP or single chain antibody to test colocalization of probes with the EGFP-tagged recombinant protein or binding of biosilica-immobilized antibodies to large and small molecule antigens, respectively. Site-directed labeling with the biarsenical probes demonstrated colocalization with EGFP-encoded proteins in nascent and mature biosilica, supporting their use in studying biosilica maturation. Isolated biosilica transformed with a single chain antibody against either the Bacillus anthracis surface layer protein EA1 or small molecule explosive trinitrotoluene (TNT) effectively boundmore » the respective antigens. A marked increase in fluorescence lifetime of the TNT surrogate Alexa Fluor 555-trinitrobenzene reflected the high binding specificity of the transformed isolated biosilica. These results demonstrated the potential use of biosilica-immobilized single chain antibodies as binders for large and small molecule antigens in sensing and therapeutics.« less

Fusion proteins comprising annexin V and Kunitz protease inhibitors are highly potent thrombogenic site-directed anticoagulants

PubMed Central

Chen, Hsiu-Hui; Vicente, Cristina P.; He, Li; Tollefsen, Douglas M.; Wun, Tze-Chein

2005-01-01

The anionic phospholipid, phosphatidyl-l-serine (PS), is sequestered in the inner layer of the plasma membrane in normal cells. Upon injury, activation, and apoptosis, PS becomes exposed on the surfaces of cells and sheds microparticles, which are procoagulant. Coagulation is initiated by formation of a tissue factor/factor VIIa complex on PS-exposed membranes and propagated through the assembly of intrinsic tenase (factor VIIIa/factor IXa), prothrombinase (factor Va/factor Xa), and factor XIa complexes on PS-exposed activated platelets. We constructed a novel series of recombinant anticoagulant fusion proteins by linking annexin V (ANV), a PS-binding protein, to the Kunitz-type protease inhibitor (KPI) domain of tick anticoagulant protein, an aprotinin mutant (6L15), amyloid β-protein precursor, or tissue factor pathway inhibitor. The resulting ANV-KPI fusion proteins were 6- to 86-fold more active than recombinant tissue factor pathway inhibitor and tick anticoagulant protein in an in vitro tissue factor–initiated clotting assay. The in vivo antithrombotic activities of the most active constructs were 3- to 10-fold higher than that of ANV in a mouse arterial thrombosis model. ANV-KPI fusion proteins represent a new class of anticoagulants that specifically target the anionic membrane-associated coagulation enzyme complexes present at sites of thrombogenesis and are potentially useful as antithrombotic agents. PMID:15677561

Impaired gamete production and viability in Atlantic croaker collected throughout the 20,000 km(2) hypoxic region in the northern Gulf of Mexico.

PubMed

Thomas, Peter; Rahman, Md Saydur; Picha, Matthew E; Tan, Wenxian

2015-12-15

The long-term impacts of recent marked increases in the incidence and extent of hypoxia (dissolved oxygen <2 mg/L) in coastal regions worldwide on fisheries and ecosystems are unknown. Reproductive impairment was investigated in Atlantic croaker collected in 2010 from the extensive coastal hypoxic region in the northern Gulf of Mexico. Potential fecundity was significantly lower in croaker collected throughout the ~20,000 km(2) hypoxic region than in croaker from normoxic sites. In vitro bioassays of gamete viability showed reductions in oocyte maturation and sperm motility in croaker collected from the hypoxic sites in response to reproductive hormones which were accompanied by decreases in gonadal levels of membrane progestin receptor alpha, the receptor regulating these processes. The finding that environmental hypoxia exposure reduces oocyte viability in addition to decreasing oocyte production in croaker suggests that fecundity estimates need to be adjusted to account for the decrease in oocyte maturation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fusion peptide of HIV-1 as a site of vulnerability to neutralizing antibody

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kong, Rui; Xu, Kai; Zhou, Tongqing

The HIV-1 fusion peptide, comprising 15 to 20 hydrophobic residues at the N terminus of the Env-gp41 subunit, is a critical component of the virus-cell entry machinery. In this paper, we report the identification of a neutralizing antibody, N123-VRC34.01, which targets the fusion peptide and blocks viral entry by inhibiting conformational changes in gp120 and gp41 subunits of Env required for entry. Crystal structures of N123-VRC34.01 liganded to the fusion peptide, and to the full Env trimer, revealed an epitope consisting of the N-terminal eight residues of the gp41 fusion peptide and glycan N88 of gp120, and molecular dynamics showedmore » that the N-terminal portion of the fusion peptide can be solvent-exposed. Finally, these results reveal the fusion peptide to be a neutralizing antibody epitope and thus a target for vaccine design.« less

Fusion peptide of HIV-1 as a site of vulnerability to neutralizing antibody

DOE PAGES

Kong, Rui; Xu, Kai; Zhou, Tongqing; ...

2016-05-13

The HIV-1 fusion peptide, comprising 15 to 20 hydrophobic residues at the N terminus of the Env-gp41 subunit, is a critical component of the virus-cell entry machinery. In this paper, we report the identification of a neutralizing antibody, N123-VRC34.01, which targets the fusion peptide and blocks viral entry by inhibiting conformational changes in gp120 and gp41 subunits of Env required for entry. Crystal structures of N123-VRC34.01 liganded to the fusion peptide, and to the full Env trimer, revealed an epitope consisting of the N-terminal eight residues of the gp41 fusion peptide and glycan N88 of gp120, and molecular dynamics showedmore » that the N-terminal portion of the fusion peptide can be solvent-exposed. Finally, these results reveal the fusion peptide to be a neutralizing antibody epitope and thus a target for vaccine design.« less

Arthroscopic partial wrist fusion.

PubMed

Ho, Pak-Cheong

2008-12-01

The wide intraarticular exposure of the wrist joint under arthroscopic view provides an excellent ground for various forms of partial wrist fusion. Combining with percutaneous fixation technique, arthroscopic partial wrist fusion can potentially generate the best possible functional outcome by preserving the maximal motion pertained with each type of partial wrist fusion because the effect of extraarticular adhesion associated with open surgery can be minimized. From November 1997 to May 2008, the author had performed 12 cases of arthroscopic partial wrist fusion, including scaphotrapeziotrapezoid fusion in 3, scaphoidectomy and 4-corner fusion in 4, radioscapholunate fusion in 3, radiolunate fusion in 1, and lunotriquetral fusion in 1 case. Through the radiocarpal or midcarpal joint, the corresponding articular surfaces were denuded of cartilage using arthroscopic burr and curette. Carpal bones involved in the fusion process were then transfixed with K wires percutaneously after alignment corrected and confirmed under fluoroscopic control. Autogenous cancellous bone graft or bone substitute were inserted and impacted to the fusion site through cannula under direct arthroscopic view. Final fixation could be by multiple K wires or cannulated screw system. Early mobilization was encouraged. Surgical complications were minor, including pin tract infection, skin burn, and delay union in 1 case. Uneventful radiologic union was obtained in 9 cases, stable fibrous union in 2, and nonunion in 1. The average follow-up period was 70 months. Symptom was resolved or improved, and functional motion was gained in all cases. All surgical scars were almost invisible, and aesthetic outcome was excellent.

Toxic money or paid altruism: the meaning of payments for identity-release gamete donors.

PubMed

Gilman, Leah

2018-05-01

Public discourses commonly frame gamete, organ and other forms of bodily donation as altruistic 'gifts'. However, despite on-going debates about the ethics of payments to donors, few studies have examined the views of donors themselves regarding the meaning of payments and their compatibility (or not) with understandings of these practices as gifts. This article addresses this issue, analysing 24 in-depth interviews with UK identity-release gamete donors. It was crucial to all participants that their donation be viewed as fundamentally other-oriented, motivated by the desire to help others. However, whilst egg donors often accommodated payment within this narrative, male participants explained that any money would taint the gift they had given. I argue that sperm donors faced particular challenges to incorporating payment within a gift narrative for two key reasons: first, sperm donors relied on a discourse of 'pure altruism', including absolute opposition between gifts and market exchange, in order to present their donation as other-oriented. In contrast, egg donors were also able to mobilise a discourse of relational giving to present their donations as a personal gift. Second, according to a continued stereotype of sperm donors as financially motivated students, their payments have already been culturally earmarked as side-line earnings. © 2018 Foundation for the Sociology of Health & Illness.

Hormonal induction of gamete release, and in-vitro fertilisation, in the critically endangered Southern Corroboree Frog, Pseudophryne corroboree

PubMed Central

2010-01-01

Background Conservation Breeding Programs (CBP's) are playing an important role in the protection of critically endangered anuran amphibians, but for many species recruitment is not successful enough to maintain captive populations, or provide individuals for release. In response, there has been an increasing focus on the use of Assisted Reproductive Technologies (ART), including the administration of reproductive hormones to induce gamete release followed by in vitro fertilisation. The objective of this study was to test the efficacy of two exogenous hormones to induce gamete release, for the purpose of conducting in vitro fertilisation (IVF), in one of Australia's most critically endangered frog species, Pseudophryne corroboree. Methods Male frogs were administered a single dose of either human chorionic gonadotropin (hCG) or luteinizing hormone-releasing hormone (LHRHa), while female frogs received both a priming and ovulatory dose of LHRHa. Spermiation responses were evaluated at 3, 7, 12, 24, 36, 48, 60 and 72 h post hormone administration (PA), and sperm number and viability were quantified using fluorescent microscopy. Ovulation responses were evaluated by stripping females every 12 h PA for 5 days. Once gametes were obtained, IVF was attempted by combining spermic urine with oocytes in a dilute solution of simplified amphibian ringer (SAR). Results Administration of both hCG and LHRHa induced approximately 80% of males to release sperm over 72 h. Peak sperm release occurred at 12 h PA for hCG treated males and 36 h PA for LHRHa treated males. On average, LHRHa treated males released a significantly higher total number of live sperm, and a higher concentration of sperm, over a longer period. In female frogs, administration of LHRHa induced approximately 30% of individuals to release eggs. On average, eggs were released between 24 and 48 h PA, with a peak in egg release at 36 h PA. IVF resulted in a moderate percentage (54.72%) of eggs being fertilised

Crystal Structure of the Pre-fusion Nipah Virus Fusion Glycoprotein Reveals a Novel Hexamer-of-Trimers Assembly.

PubMed

Xu, Kai; Chan, Yee-Peng; Bradel-Tretheway, Birgit; Akyol-Ataman, Zeynep; Zhu, Yongqun; Dutta, Somnath; Yan, Lianying; Feng, YanRu; Wang, Lin-Fa; Skiniotis, Georgios; Lee, Benhur; Zhou, Z Hong; Broder, Christopher C; Aguilar, Hector C; Nikolov, Dimitar B

2015-12-01

Nipah virus (NiV) is a paramyxovirus that infects host cells through the coordinated efforts of two envelope glycoproteins. The G glycoprotein attaches to cell receptors, triggering the fusion (F) glycoprotein to execute membrane fusion. Here we report the first crystal structure of the pre-fusion form of the NiV-F glycoprotein ectodomain. Interestingly this structure also revealed a hexamer-of-trimers encircling a central axis. Electron tomography of Nipah virus-like particles supported the hexameric pre-fusion model, and biochemical analyses supported the hexamer-of-trimers F assembly in solution. Importantly, structure-assisted site-directed mutagenesis of the interfaces between F trimers highlighted the functional relevance of the hexameric assembly. Shown here, in both cell-cell fusion and virus-cell fusion systems, our results suggested that this hexamer-of-trimers assembly was important during fusion pore formation. We propose that this assembly would stabilize the pre-fusion F conformation prior to cell attachment and facilitate the coordinated transition to a post-fusion conformation of all six F trimers upon triggering of a single trimer. Together, our data reveal a novel and functional pre-fusion architecture of a paramyxoviral fusion glycoprotein.

Human testicular protein TPX1/CRISP-2: localization in spermatozoa, fate after capacitation and relevance for gamete interaction.

PubMed

Busso, D; Cohen, D J; Hayashi, M; Kasahara, M; Cuasnicú, P S

2005-04-01

Testicular protein Tpx-1, also known as CRISP-2, is a cysteine-rich secretory protein specifically expressed in the male reproductive tract. Since the information available on the human protein is limited to the identification and expression of its gene, in this work we have studied the presence and localization of human Tpx-1 (TPX1) in sperm, its fate after capacitation and acrosome reaction (AR), and its possible involvement in gamete interaction. Indirect immunofluorescence studies revealed the absence of significant staining in live or fixed non-permeabilized sperm, in contrast to a clear labelling in the acrosomal region of permeabilized sperm. These results, together with complementary evidence from protein extraction procedures strongly support that TPX1 would be mainly an intra-acrosomal protein in fresh sperm. After in vitro capacitation and ionophore-induced AR, TPX1 remained associated with the equatorial segment of the acrosome. The lack of differences in the electrophoretic mobility of TPX1 before and after capacitation and AR indicates that the protein would not undergo proteolytical modifications during these processes. The possible involvement of TPX1 in gamete interaction was evaluated by the hamster oocyte penetration test. The presence of anti-TPX1 during gamete co-incubation produced a significant and dose-dependent inhibition in the percentage of penetrated zona-free hamster oocytes without affecting sperm motility, the AR or sperm binding to the oolema. Together, these results indicate that human TPX1 would be a component of the sperm acrosome that remains associated with sperm after capacitation and AR, and is relevant for sperm-oocyte interaction.

cGAS-Mediated Innate Immunity Spreads Intercellularly through HIV-1 Env-Induced Membrane Fusion Sites.

PubMed

Xu, Shuting; Ducroux, Aurélie; Ponnurangam, Aparna; Vieyres, Gabrielle; Franz, Sergej; Müsken, Mathias; Zillinger, Thomas; Malassa, Angelina; Ewald, Ellen; Hornung, Veit; Barchet, Winfried; Häussler, Susanne; Pietschmann, Thomas; Goffinet, Christine

2016-10-12

Upon sensing cytoplasmic retroviral DNA in infected cells, cyclic GMP-AMP (cGAMP) synthase (cGAS) produces the cyclic dinucleotide cGAMP, which activates STING to trigger a type I interferon (IFN) response. We find that membrane fusion-inducing contact between donor cells expressing the HIV envelope (Env) and primary macrophages endogenously expressing the HIV receptor CD4 and coreceptor enable intercellular transfer of cGAMP. This cGAMP exchange results in STING-dependent antiviral IFN responses in target macrophages and protection from HIV infection. Furthermore, under conditions allowing cell-to-cell transmission of HIV-1, infected primary T cells, but not cell-free virions, deliver cGAMP to autologous macrophages through HIV-1 Env and CD4/coreceptor-mediated membrane fusion sites and induce a STING-dependent, but cGAS-independent, IFN response in target cells. Collectively, these findings identify an infection-specific mode of horizontal transfer of cGAMP between primary immune cells that may boost antiviral responses, particularly in infected tissues in which cell-to-cell transmission of virions exceeds cell-free infection. Copyright © 2016 Elsevier Inc. All rights reserved.

Distinct Requirements for HIV-Cell Fusion and HIV-mediated Cell-Cell Fusion*

PubMed Central

Kondo, Naoyuki; Marin, Mariana; Kim, Jeong Hwa; Desai, Tanay M.; Melikyan, Gregory B.

2015-01-01

Whether HIV-1 enters cells by fusing with the plasma membrane or with endosomes is a subject of active debate. The ability of HIV-1 to mediate fusion between adjacent cells, a process referred to as “fusion-from-without” (FFWO), shows that this virus can fuse with the plasma membrane. To compare FFWO occurring at the cell surface with HIV-cell fusion through a conventional entry route, we designed an experimental approach that enabled the measurements of both processes in the same sample. The following key differences were observed. First, a very small fraction of viruses fusing with target cells participated in FFWO. Second, whereas HIV-1 fusion with adherent cells was insensitive to actin inhibitors, post-CD4/coreceptor binding steps during FFWO were abrogated. A partial dependence of HIV-cell fusion on actin remodeling was observed in CD4+ T cells, but this effect appeared to be due to the actin dependence of virus uptake. Third, deletion of the cytoplasmic tail of HIV-1 gp41 dramatically enhanced the ability of the virus to promote FFWO, while having a modest effect on virus-cell fusion. Distinct efficiencies and actin dependences of FFWO versus HIV-cell fusion are consistent with the notion that, except for a minor fraction of particles that mediate fusion between the plasma membranes of adjacent cells, HIV-1 enters through an endocytic pathway. We surmise, however, that cell-cell contacts enabling HIV-1 fusion with the plasma membrane could be favored at the sites of high density of target cells, such as lymph nodes. PMID:25589785

Comparative study of the germination of Ulva prolifera gametes on various substrates

NASA Astrophysics Data System (ADS)

Geng, Huixia; Yan, Tian; Zhou, Mingjiang; Liu, Qing

2015-09-01

Since 2007, massive green tides have occurred every summer in the southern Yellow Sea (YS), China. They have caused severe ecological consequences and huge economic losses. Ulva prolifera originated from Subei Shoal of the YS was confirmed as causative species of the green tides. The Porphyra yezoensis aquaculture rafts in the Subei Shoal have been highly suspected to be the "seed bed" of the green tides, because U. prolifera abundantly fouled the Porphyra yezoensis aquaculture facilities. Besides, various habitats of aquaculture ponds along the Jiangsu coastline and mudflat in the Subei Shoal were proposed to be possible sources of green tides. To understand the "seed" of the green tides in the southern YS and mitigate the original biomass of the green tide, various materials used as substrates for the germination of U. prolifera gametes were tested in this study. Culture experiments showed the following: 1) materials used in the P. yezoensis rafts (plastic, bamboo, jute rope, plastic rope, nylon netting, and plastic netting) displayed a significantly higher germination rate than those associated with mudflats and aquaculture ponds (mud, sand and rock); 2) plastics were the best substrates for the germination of U. prolifera gametes; 3) poor germination was found on old fronds of U. prolifera,, and rubber showed inhibitory effect on germination. The success in germination on P. yezoensis rafts related materials supports the notion that these mariculture structures may be involved in acting as a seed bed for green tide macroalgae. The lack of germination on rubber surfaces may suggest one way to limit the proliferation of early stages of U. prolifera.

Impaired sperm fertilizing ability in mice lacking Cysteine-RIch Secretory Protein 1 (CRISP1)

PubMed Central

Da Ros, Vanina G.; Maldera, Julieta A.; Willis, William D.; Cohen, Débora J.; Goulding, Eugenia H.; Gelman, Diego M.; Rubinstein, Marcelo; Eddy, Edward M.; Cuasnicu, Patricia S.

2008-01-01

Mammalian fertilization is a complex multi-step process mediated by different molecules present on both gametes. Epididymal protein CRISP1, a member of the Cysteine-RIch Secretory Protein (CRISP) family, was identified by our laboratory and postulated to participate in both sperm-zona pellucida (ZP) interaction and gamete fusion by binding to egg-complementary sites. To elucidate the functional role of CRISP1 in vivo, we disrupted the Crisp1 gene and evaluated the effect on animal fertility and several sperm parameters. Male and female Crisp1−/− animals exhibited no differences in fertility compared to controls. Sperm motility and the ability to undergo a spontaneous or progesterone-induced acrosome reaction were neither affected in Crisp1−/− mice. However, the level of protein tyrosine phosphorylation during capacitation was clearly lower in mutant sperm than in controls. In vitro fertilization assays showed that Crisp1−/− sperm also exhibited a significantly reduced ability to penetrate both ZP-intact and ZP-free eggs. Moreover, when ZP-free eggs were simultaneously inseminated with Crisp1+/+ and Crisp1−/− sperm in a competition assay, the mutant sperm exhibited a greater disadvantage in their fusion ability. Finally, the finding that the fusion ability of Crisp1−/− sperm was further inhibited by the presence of CRISP1 or CRISP2 during gamete co-incubation, supports that another CRISP cooperates with CRISP1 during fertilization and might compensate for its lack in the mutant mice. Together, these results indicate that CRISP proteins are players in the mammalian fertilization process. To our knowledge this is the first knockout mice generated for a CRISP protein. The information obtained might have important functional implications for other members of the widely distributed and evolutionarily conserved CRISP family. PMID:18571638

Mettl3 Mutation Disrupts Gamete Maturation and Reduces Fertility in Zebrafish.

PubMed

Xia, Hui; Zhong, Chengrong; Wu, Xingxing; Chen, Ji; Tao, Binbin; Xia, Xiaoqin; Shi, Mijuan; Zhu, Zuoyan; Trudeau, Vance L; Hu, Wei

2018-02-01

N 6 -methyladenosine (m 6 A), catalyzed by Mettl3 methyltransferase, is a highly conserved epigenetic modification in eukaryotic messenger RNA (mRNA). Previous studies have implicated m 6 A modification in multiple biological processes, but the in vivo function of m 6 A has been difficult to study, because mettl3 mutants are embryonic lethal in both mammals and plants. In this study, we have used transcription activator-like effector nucleases and generated viable zygotic mettl3 mutant, Z mettl3 m/m , in zebrafish. We find that the oocytes in Z mettl3 m/m adult females are stalled in early development and the ratio of full-grown stage (FG) follicles is significantly lower than that of wild type. Human chorionic gonadotropin-induced ovarian germinal vesicle breakdown in vitro and the numbers of eggs ovulated in vivo are both decreased as well, while the defects of oocyte maturation can be rescued by sex hormone in vitro and in vivo In Z mettl3 m/m adult males, we find defects in sperm maturation and sperm motility is significantly reduced. Further study shows that 11-ketotestosterone (11-KT) and 17β-estradiol (E2) levels are significantly decreased in Z mettl3 m/m , and defective gamete maturation is accompanied by decreased overall m 6 A modification levels and disrupted expression of genes critical for sex hormone synthesis and gonadotropin signaling in Z mettl3 m/m Thus, our study provides the first in vivo evidence that loss of Mettl3 leads to failed gamete maturation and significantly reduced fertility in zebrafish. Mettl3 and m 6 A modifications are essential for optimal reproduction in vertebrates. Copyright © 2018 by the Genetics Society of America.

Identification and localization of the sperm CRISP family protein CiUrabin involved in gamete interaction in the ascidian Ciona intestinalis.

PubMed

Yamaguchi, Akira; Saito, Takako; Yamada, Lixy; Taniguchi, Hisaaki; Harada, Yoshito; Sawada, Hitoshi

2011-07-01

Ascidians are hermaphrodites, and most release sperm and eggs nearly simultaneously. Many species, including Halocynthia roretzi and Ciona intestinalis, are self-sterile. We previously reported that the interaction between a 12 EGF-like repeat-containing vitelline-coat (VC) protein, HrVC70, and a sperm GPI-anchored CRISP, HrUrabin, in lipid rafts plays a key role in self-/nonself-recognizable gamete interaction in H. roretzi. On the other hand, we recently identified two pairs of polymorphic genes responsible for self-incompatibility in C. intestinalis by positional cloning: The sperm polycystin 1-like receptors s-Themis-A/B and its fibrinogen-like ligand v-Themis-A/B on the VC. However, it is not known if the orthologs of HrVC70 and HrUrabin also participate in gamete interaction in C. intestinalis since they are from different orders. Here, we tested for a C. intestinalis ortholog (CiUrabin) of HrUrabin by searching the genome database and proteomes of sperm lipid rafts. The identified CiUrabin belongs to the CRISP family, with a PR domain and a GPI-anchor-attachment site. CiUrabin appears to be specifically expressed in the testis and localized at the surface of the sperm head, as revealed by Northern blotting and immunocytochemistry, respectively. The specific interaction between CiVC57, a C. intestinalis ortholog of HrVC70, and CiUrabin was confirmed by Far Western analysis, similarly to the interaction between HrVC70 and HrUrabin. The molecular interaction between CiVC57 and CiUrabin may be involved in the primary binding of sperm to the VC prior to the allorecognition process, mediated by v-Themis-A/B and s-Themis-A/B, during fertilization of C. intestinalis. Copyright © 2011 Wiley-Liss, Inc.

The attitudes of IVF patients treated in the Czech Republic towards informing children born after gamete donation.

PubMed

Rumpikova, Tatana; Oborna, Ivana; Belaskova, Silvie; Konecna, Hana; Rumpik, David

2018-03-01

In recent decades gamete donation has received growing attention. Data from the Czech National Registry of Assisted Reproduction show that the number of cycles using donated oocytes has been increasing every year. According to Czech law, gamete donation is anonymous. Since 2011, some members of the Czech parliament have repeatedly made requests to revoke the anonymity but anonymity is one of the preconditions for such donation in this country. The aim of this study was to find out how the gamete recipients feel towards informing their child about the circumstances of their conception and their access to the identity of the donor. A total of 195 recipients (122 women undergoing treatment - 43 Czechs, 79 foreigners (Western Europe and the USA) and 73 male partners - 28 Czechs, 45 foreigners) participated in this survey. The data were obtained by anonymous questionnaire. A significant difference between the attitude of the future Czech and foreign parents regarding disclosing the mode of conception was found (P = 0.003). The vast majority of Czechs were against disclosure. The foreign recipients were somewhat more divided. Regarding the donor's identity, there was no difference in atttitude between the groups. Recipients rarely consider that the knowledge of the donor's identity will be important for their child. The recipients overall, were convinced that the psychological aspects of parenting are far more important to the child than genetics, and see no reasons for disclosing the donor´s identity. While the the foreign recipients were less adamant about non-disclosure, the overall finding was in accord with the current Czech law on anonymity and not in agreement with the proposed abolition. The recipient's attitudes towards disclosing were also culturally determined. The fact that some countries have revised their rules towards open idendity is not a rationale for such change in the Czech Republic.

Progress, challenges and perspectives on fish gamete cryopreservation: A mini-review.

PubMed

Asturiano, Juan F; Cabrita, Elsa; Horváth, Ákos

2017-05-01

Protocols for the cryopreservation of fish gametes have been developed for many different fish species, in special, freshwater salmonids and cyprinids. Methods for sperm freezing have progressed during the last decades due to the increasing number of potential applications: aquaculture (genetic improvement programs, broodstock management, helping with species having reproductive problems), biotechnology studies using model fish species (preservation of transgenic or mutant lines), cryobanking of genetic resources from endangered species, etc. This mini-review tries to give an overview of the present situation of this area of research, identifying the main challenges and perspectives, redirecting the reader to more in-depth reviews and papers. Copyright © 2016 Elsevier Inc. All rights reserved.

Protection against de novo methylation is instrumental in maintaining parent-of-origin methylation inherited from the gametes.

PubMed

Proudhon, Charlotte; Duffié, Rachel; Ajjan, Sophie; Cowley, Michael; Iranzo, Julian; Carbajosa, Guillermo; Saadeh, Heba; Holland, Michelle L; Oakey, Rebecca J; Rakyan, Vardhman K; Schulz, Reiner; Bourc'his, Déborah

2012-09-28

Identifying loci with parental differences in DNA methylation is key to unraveling parent-of-origin phenotypes. By conducting a MeDIP-Seq screen in maternal-methylation free postimplantation mouse embryos (Dnmt3L-/+), we demonstrate that maternal-specific methylation exists very scarcely at midgestation. We reveal two forms of oocyte-specific methylation inheritance: limited to preimplantation, or with longer duration, i.e. maternally imprinted loci. Transient and imprinted maternal germline DMRs (gDMRs) are indistinguishable in gametes and preimplantation embryos, however, de novo methylation of paternal alleles at implantation delineates their fates and acts as a major leveling factor of parent-inherited differences. We characterize two new imprinted gDMRs, at the Cdh15 and AK008011 loci, with tissue-specific imprinting loss, again by paternal methylation gain. Protection against demethylation after fertilization has been emphasized as instrumental in maintaining parent-of-origin methylation inherited from the gametes. Here we provide evidence that protection against de novo methylation acts as an equal major pivot, at implantation and throughout life. Copyright © 2012 Elsevier Inc. All rights reserved.

Protection against De Novo Methylation Is Instrumental in Maintaining Parent-of-Origin Methylation Inherited from the Gametes

PubMed Central

Proudhon, Charlotte; Duffié, Rachel; Ajjan, Sophie; Cowley, Michael; Iranzo, Julian; Carbajosa, Guillermo; Saadeh, Heba; Holland, Michelle L.; Oakey, Rebecca J.; Rakyan, Vardhman K.; Schulz, Reiner; Bourc’his, Déborah

2012-01-01

Summary Identifying loci with parental differences in DNA methylation is key to unraveling parent-of-origin phenotypes. By conducting a MeDIP-Seq screen in maternal-methylation free postimplantation mouse embryos (Dnmt3L-/+), we demonstrate that maternal-specific methylation exists very scarcely at midgestation. We reveal two forms of oocyte-specific methylation inheritance: limited to preimplantation, or with longer duration, i.e. maternally imprinted loci. Transient and imprinted maternal germline DMRs (gDMRs) are indistinguishable in gametes and preimplantation embryos, however, de novo methylation of paternal alleles at implantation delineates their fates and acts as a major leveling factor of parent-inherited differences. We characterize two new imprinted gDMRs, at the Cdh15 and AK008011 loci, with tissue-specific imprinting loss, again by paternal methylation gain. Protection against demethylation after fertilization has been emphasized as instrumental in maintaining parent-of-origin methylation inherited from the gametes. Here we provide evidence that protection against de novo methylation acts as an equal major pivot, at implantation and throughout life. PMID:22902559

The Formin Diaphanous Regulates Myoblast Fusion through Actin Polymerization and Arp2/3 Regulation

PubMed Central

Deng, Su; Bothe, Ingo; Baylies, Mary K.

2015-01-01

The formation of multinucleated muscle cells through cell-cell fusion is a conserved process from fruit flies to humans. Numerous studies have shown the importance of Arp2/3, its regulators, and branched actin for the formation of an actin structure, the F-actin focus, at the fusion site. This F-actin focus forms the core of an invasive podosome-like structure that is required for myoblast fusion. In this study, we find that the formin Diaphanous (Dia), which nucleates and facilitates the elongation of actin filaments, is essential for Drosophila myoblast fusion. Following cell recognition and adhesion, Dia is enriched at the myoblast fusion site, concomitant with, and having the same dynamics as, the F-actin focus. Through analysis of Dia loss-of-function conditions using mutant alleles but particularly a dominant negative Dia transgene, we demonstrate that reduction in Dia activity in myoblasts leads to a fusion block. Significantly, no actin focus is detected, and neither branched actin regulators, SCAR or WASp, accumulate at the fusion site when Dia levels are reduced. Expression of constitutively active Dia also causes a fusion block that is associated with an increase in highly dynamic filopodia, altered actin turnover rates and F-actin distribution, and mislocalization of SCAR and WASp at the fusion site. Together our data indicate that Dia plays two roles during invasive podosome formation at the fusion site: it dictates the level of linear F-actin polymerization, and it is required for appropriate branched actin polymerization via localization of SCAR and WASp. These studies provide new insight to the mechanisms of cell-cell fusion, the relationship between different regulators of actin polymerization, and invasive podosome formation that occurs in normal development and in disease. PMID:26295716

Cryopreservation of Adult Male Spring and Summer Chinook Salmon Gametes in the Snake River Basin, 1997 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faurot, Dave; Kucera, Paul A.; Armstrong, Robyn D.

1998-06-01

Chinook salmon populations in the Northwest are decreasing in number. The Nez Perce Tribe was funded in 1997 by the Bonneville Power Administration to coordinate and initiate gene banking of adult male gametes from Endangered Species Act (ESA) listed spring and summer chinook salmon in the Snake River basin.

Sex ratio and gamete size across eastern North America in Dictyostelium discoideum, a social amoeba with three sexes.

PubMed

Douglas, T E; Strassmann, J E; Queller, D C

2016-07-01

Theory indicates that numbers of mating types should tend towards infinity or remain at two. The social amoeba, Dictyostelium discoideum, however, has three mating types. It is therefore a mystery how this species has broken the threshold of two mating types, but has not increased towards a much higher number. Frequency-dependent selection on rare types in combination with isogamy, a form of reproduction involving gametes similar in size, could explain the evolution of multiple mating types in this system. Other factors, such as drift, may be preventing the evolution of more than three. We first looked for evidence of isogamy by measuring gamete size associated with each type. We found no evidence of size dissimilarities between gametes. We then looked for evidence of balancing selection, by examining mating type distributions in natural populations and comparing genetic differentiation at the mating type locus to that at more neutral loci. We found that mating type frequency varied among the three populations we examined, with only one of the three showing an even sex ratio, which does not support balancing selection. However, we found more population structure at neutral loci than the mating type locus, suggesting that the three mating types are indeed maintained at intermediate frequencies by balancing selection. Overall, the data are consistent with balancing selection acting on D. discoideum mating types, but with a sufficiently weak rare sex advantage to allow for drift, a potential explanation for why these amoebae have only three mating types. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Telomeres and mechanisms of Robertsonian fusion.

PubMed

Slijepcevic, P

1998-05-01

The Robertsonian (Rb) fusion, a chromosome rearrangement involving centric fusion of two acro-(telo)centric chromosomes to form a single metacentric, is one of the most frequent events in mammalian karyotype evolution. Since one of the functions of telomeres is to preserve chromosome integrity, a prerequisite for the formation of Rb fusions should be either telomere loss or telomere inactivation. Possible mechanisms underlying the formation of various types of Rb fusion are discussed here. For example, Rb fusion in wild mice involves complete loss of p-arm telomeres by chromosome breakage within minor satellite sequences. By contrast, interstitial telomeric sites are found in the pericentromeric regions of chromosomes originating from a number of vertebrate species, suggesting the occurrence of Rb-like fusion without loss of telomeres, a possibility consistent with some form of telomere inactivation. Finally, a recent study suggests that telomere shortening induced by the deletion of the telomerase RNA gene in the mouse germ-line leads to telomere loss and high frequencies of Rb fusion in mouse somatic cells. Thus, at least three mechanisms in mammalian cells lead to the formation of Rb fusions.

Salmonid Gamete Preservation in the Snake River Basin : 2000 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Robyn; Kucera, Paul A.

2001-06-01

Steelhead (Oncorhynchus mykiss) and chinook salmon (Oncorhynchus tshawytscha) populations in the Northwest are decreasing. Genetic diversity is being lost at an alarming rate. The Nez Perce Tribe (Tribe) strives to ensure availability of genetic samples of the existing male salmonid population by establishing and maintaining a germplasm repository. The sampling strategy, initiated in 1992, has been to collect and preserve male salmon and steelhead genetic diversity across the geographic landscape by sampling within the major river subbasins in the Snake River basin, assuming a metapopulation structure existed historically. Gamete cryopreservation conserves genetic diversity in a germplasm repository, but is notmore » a recovery action for listed fish species. The Tribe was funded in 2000 by the Bonneville Power Administration (BPA) and the U.S. Fish and Wildlife Service Lower Snake River Compensation Plan (LSRCP) to coordinate gene banking of male gametes from Endangered Species Act listed steelhead and spring and summer chinook salmon in the Snake River basin. In 2000, a total of 349 viable chinook salmon semen samples from the Lostine River, Catherine Creek, upper Grande Ronde River, Lookingglass Hatchery (Imnaha River stock), Rapid River Hatchery, Lake Creek, the South Fork Salmon River weir, Johnson Creek, Big Creek, Capehorn Creek, Marsh Creek, Pahsimeroi Hatchery, and Sawtooth Hatchery (upper Salmon River stock) were cryopreserved. Also, 283 samples of male steelhead gametes from Dworshak Hatchery, Fish Creek, Grande Ronde River, Imnaha River, Little Sheep Creek, Pahsimeroi Hatchery and Oxbow Hatchery were also cryopreserved. The Tribe acquired 5 frozen steelhead samples from the Selway River collected in 1994 and 15 from Fish Creek sampled in 1993 from the U.S. Geological Survey, for addition into the germplasm repository. Also, 590 cryopreserved samples from the Grande Ronde chinook salmon captive broodstock program are being stored at the University of

Melatonin Scavenger Properties against Oxidative and Nitrosative Stress: Impact on Gamete Handling and In Vitro Embryo Production in Humans and Other Mammals

PubMed Central

Loren, Pía; Sánchez, Raúl; Arias, María-Elena; Felmer, Ricardo; Risopatrón, Jennie; Cheuquemán, Carolina

2017-01-01

Oxidative and nitrosative stress are common problems when handling gametes in vitro. In vitro development in mammalian embryos is highly affected by culture conditions, especially by reactive oxygen species (ROS) and reactive nitrogen species (RNS), because their absence or overproduction causes embryo arrest and changes in gene expression. Melatonin in gamete co-incubation during in vitro fertilization (IVF) has deleterious or positive effects, depending on the concentration used in the culture medium, demonstrating the delicate balance between antioxidant and pro-oxidant activity. Further research is needed to better understand the possible impact of melatonin on the different IVP steps in humans and other mammals, especially in seasonal breeds where this neuro-hormone system highly regulates its reproduction physiology. PMID:28613231

Evolutionary history of the HAP2/GCS1 gene and sexual reproduction in metazoans.

PubMed

Steele, Robert E; Dana, Catherine E

2009-11-03

The HAP2/GCS1 gene first appeared in the common ancestor of plants, animals, and protists, and is required in the male gamete for fusion to the female gamete in the unicellular organisms Chlamydomonas and Plasmodium. We have identified a HAP2/GCS1 gene in the genome sequence of the sponge Amphimedon queenslandica. This finding provides a continuous evolutionary history of HAP2/GCS1 from unicellular organisms into the metazoan lineage. Divergent versions of the HAP2/GCS1 gene are also present in the genomes of some but not all arthropods. By examining the expression of the HAP2/GCS1 gene in the cnidarian Hydra, we have found the first evidence supporting the hypothesis that HAP2/GCS1 was used for male gamete fusion in the ancestor of extant metazoans and that it retains that function in modern cnidarians.

Endocrine-disrupting chemicals in aquatic environment: what are the risks for fish gametes?

PubMed

Carnevali, Oliana; Santangeli, Stefania; Forner-Piquer, Isabel; Basili, Danilo; Maradonna, Francesca

2018-06-11

Over the past 25 years, extensive research in vertebrate species has identified several genomic pathways altered by exposures to anthropogenic chemicals with hormone-like activity mediated by their interaction with nuclear receptors. In addition, many pollutants have been shown to interfere with non-genomic (non-classical) pathways, but this mechanism of endocrine disruption is still poorly understood. Recently, the number of publications describing the effects of Endocrine disrupting chemicals (EDCs) on fish reproduction, focusing on the deregulation of the hypothalamus-pituitary-gonadal axis as well as on gamete quality, significantly increased. Depending on their ability to mimic endogenous hormones, the may differently affect male or female reproductive physiology. Inhibition of gametogenesis, development of intersex gonads, alteration of the gonadosomatic index, and decreased fertility rate have been largely documented. In males, alterations of sperm density, motility, and fertility have been observed in several wild species. Similar detrimental effects were described in females, including negative outcomes on oocyte growth and maturation plus the occurrence of apoptotic/autophagic processes. These pathways may affect gamete viability considered as one of the major indicators of reproductive endocrine disruption. Pollutants act also at DNA level producing DNA mutations and changes in epigenetic pathways inducing specific mechanisms of toxicity and/or aberrant cellular responses that may affect subsequent generation(s) through the germline. In conclusion, this review summarizes the effects caused by EDC exposure on fish reproduction, focusing on gametogenesis, giving a general overview of the different aspects dealing with this issue, from morphological alteration, deregulation of steroidogenesis, hormonal synthesis, and occurrence of epigenetic process.

Asymmetric Mbc, active Rac1 and F-actin foci in the fusion-competent myoblasts during myoblast fusion in Drosophila

PubMed Central

Haralalka, Shruti; Shelton, Claude; Cartwright, Heather N.; Katzfey, Erin; Janzen, Evan; Abmayr, Susan M.

2011-01-01

Myoblast fusion is an intricate process that is initiated by cell recognition and adhesion, and culminates in cell membrane breakdown and formation of multinucleate syncytia. In the Drosophila embryo, this process occurs asymmetrically between founder cells that pattern the musculature and fusion-competent myoblasts (FCMs) that account for the bulk of the myoblasts. The present studies clarify and amplify current models of myoblast fusion in several important ways. We demonstrate that the non-conventional guanine nucleotide exchange factor (GEF) Mbc plays a fundamental role in the FCMs, where it functions to activate Rac1, but is not required in the founder cells for fusion. Mbc, active Rac1 and F-actin foci are highly enriched in the FCMs, where they localize to the Sns:Kirre junction. Furthermore, Mbc is crucial for the integrity of the F-actin foci and the FCM cytoskeleton, presumably via its activation of Rac1 in these cells. Finally, the local asymmetric distribution of these proteins at adhesion sites is reminiscent of invasive podosomes and, consistent with this model, they are enriched at sites of membrane deformation, where the FCM protrudes into the founder cell/myotube. These data are consistent with models promoting actin polymerization as the driving force for myoblast fusion. PMID:21389053

Fusion technologies for Laser Inertial Fusion Energy (LIFE)

NASA Astrophysics Data System (ADS)

Kramer, K. J.; Latkowski, J. F.; Abbott, R. P.; Anklam, T. P.; Dunne, A. M.; El-Dasher, B. S.; Flowers, D. L.; Fluss, M. J.; Lafuente, A.; Loosmore, G. A.; Morris, K. R.; Moses, E.; Reyes, S.

2013-11-01

The Laser Inertial Fusion-based Energy (LIFE) engine design builds upon on going progress at the National Ignition Facility (NIF) and offers a near-term pathway to commercial fusion. Fusion technologies that are critical to success are reflected in the design of the first wall, blanket and tritium separation subsystems. The present work describes the LIFE engine-related components and technologies. LIFE utilizes a thermally robust indirect-drive target and a chamber fill gas. Coolant selection and a large chamber solid-angle coverage provide ample tritium breeding margin and high blanket gain. Target material selection eliminates the need for aggressive chamber clearing, while enabling recycling. Demonstrated tritium separation and storage technologies limit the site tritium inventory to attractive levels. These key technologies, along with the maintenance and advanced materials qualification program have been integrated into the LIFE delivery plan. This describes the development of components and subsystems, through prototyping and integration into a First Of A Kind power plant. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Case reports to suggest an algorithm for management of total fertilisation failure prior to use of donor gametes.

PubMed

Nicopoullos, James D M; Whitney, E; Wells, V; Batha, S; Faris, R; Abdalla, H

2015-11-01

Total fertilisation failure (TFF), even with intracytoplasmic sperm injection (ICSI), occurs in approximately 3 % of cycles, can be recurrent and the exact cause is difficult to elucidate. Differentiation between oocyte and sperm-related cause of TFF is possible using mouse oocyte-activation techniques, but is not an option within most clinical settings. Therefore, the management of these couples is clinically driven, and the endpoint, if recurrent, is often the use of donor gametes. However, with the invariable lack of a definitive cause of TFF, any decision between the use of donor sperm or oocytes remains an emotive one. We present two case reports demonstrating the importance of appropriate investigation, activation techniques (mechanical and chemical) and clinical management options to develop a clinical algorithm prior to the use of donor gametes. This study is composed of two case reports of assisted reproduction investigation and treatment within an assisted conception unit for couples with recurrent total fertilisation failure. Using appropriate investigation (endocrine, urological and embryological) and treatments (ICSI, IMSI, oocyte-activation techniques), a fertilisation rate of 48 % was achieved in two cycles in couples following a total of nine previous cycles (and 200 previously collected eggs) with TFF. Oocyte activation requires the triggering of intracellular calcium oscillations by the release of a sperm-specific factor (phospholipase C zeta (PLCζ)) into the oocyte cytoplasm. Although, PLCζ deficiencies have been demonstrated as putative causes of failed activation, impaired oocyte responsiveness may also be a factor. The use of donor gametes is often recommended and is often the required endpoint of treatment. However, these reports outline a clinical algorithm that potentially offers success without donation, and also offers a systematic approach to help decide whether donor oocytes or sperm should be recommended.

The end of donor anonymity: how genetic testing is likely to drive anonymous gamete donation out of business.

PubMed

Harper, Joyce C; Kennett, Debbie; Reisel, Dan

2016-06-01

Thousands of people worldwide have been conceived using donor gametes, but not all parents tell their children of their origin. Several countries now allow donor-conceived offspring to potentially know their genetic parent if they are informed of their donor-conceived status. At the same time, personal genetic testing is a rapidly expanding field. Over 3 million people have already used direct-to-consumer genetic testing to find information about their ancestry, and many are participating in international genetic genealogy databases that will match them with relatives. The increased prevalence of these technologies poses numerous challenges to the current practice of gamete donation. (i) Whether they are donating in a country that practices anonymous donation or not, donors should be informed that their anonymity is not guaranteed, as they may be traced if their DNA, or that of a relative, is added to a database. (ii) Donor-conceived adults who have not been informed of their status may find out that they are donor-conceived. (iii) Parents using donor conception need to be fully informed that their children's DNA will identify that they are not the biological parents and they should be encouraged to disclose the use of donor gametes to their children. Together, these concerns make urgent a wide-ranging societal conversation about how to best safeguard and promote the interests of donor-conceived offspring and protect the rights of donors. Specifically, there is a need to ensure that new genetic information is communicated in a way that promotes both the safety and the privacy rights of offspring and donors alike. All parties concerned must be aware that, in 2016, donor anonymity does not exist. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Dynamic F-actin movement is essential for fertilization in Arabidopsis thaliana

PubMed Central

Kawashima, Tomokazu; Maruyama, Daisuke; Shagirov, Murat; Li, Jing; Hamamura, Yuki; Yelagandula, Ramesh; Toyama, Yusuke; Berger, Frédéric

2014-01-01

In animals, microtubules and centrosomes direct the migration of gamete pronuclei for fertilization. By contrast, flowering plants have lost essential components of the centrosome, raising the question of how flowering plants control gamete nuclei migration during fertilization. Here, we use Arabidopsis thaliana to document a novel mechanism that regulates F-actin dynamics in the female gametes and is essential for fertilization. Live imaging shows that F-actin structures assist the male nucleus during its migration towards the female nucleus. We identify a female gamete-specific Rho-GTPase that regulates F-actin dynamics and further show that actin–myosin interactions are also involved in male gamete nucleus migration. Genetic analyses and imaging indicate that microtubules are dispensable for migration and fusion of male and female gamete nuclei. The innovation of a novel actin-based mechanism of fertilization during plant evolution might account for the complete loss of the centrosome in flowering plants. DOI: http://dx.doi.org/10.7554/eLife.04501.001 PMID:25303363

The Quality and Readability of Information Available on the Internet Regarding Lumbar Fusion

PubMed Central

Zhang, Dafang; Schumacher, Charles; Harris, Mitchel B.; Bono, Christopher M.

2015-01-01

Study Design An Internet-based evaluation of Web sites regarding lumbar fusion. Objective The Internet has become a major resource for patients; however, the quality and readability of Internet information regarding lumbar fusion is unclear. The objective of this study is to evaluate the quality and readability of Internet information regarding lumbar fusion and to determine whether these measures changed with Web site modality, complexity of the search term, or Health on the Net Code of Conduct certification. Methods Using five search engines and three different search terms of varying complexity (“low back fusion,” “lumbar fusion,” and “lumbar arthrodesis”), we identified and reviewed 153 unique Web site hits for information quality and readability. Web sites were specifically analyzed by search term and Web site modality. Information quality was evaluated on a 5-point scale. Information readability was assessed using the Flesch-Kincaid score for reading grade level. Results The average quality score was low. The average reading grade level was nearly six grade levels above that recommended by National Work Group on Literacy and Health. The quality and readability of Internet information was significantly dependent on Web site modality. The use of more complex search terms yielded information of higher reading grade level but not higher quality. Conclusions Higher-quality information about lumbar fusion conveyed using language that is more readable by the general public is needed on the Internet. It is important for health care providers to be aware of the information accessible to patients, as it likely influences their decision making regarding care. PMID:26933614

The Quality and Readability of Information Available on the Internet Regarding Lumbar Fusion.

PubMed

Zhang, Dafang; Schumacher, Charles; Harris, Mitchel B; Bono, Christopher M

2016-03-01

Study Design An Internet-based evaluation of Web sites regarding lumbar fusion. Objective The Internet has become a major resource for patients; however, the quality and readability of Internet information regarding lumbar fusion is unclear. The objective of this study is to evaluate the quality and readability of Internet information regarding lumbar fusion and to determine whether these measures changed with Web site modality, complexity of the search term, or Health on the Net Code of Conduct certification. Methods Using five search engines and three different search terms of varying complexity ("low back fusion," "lumbar fusion," and "lumbar arthrodesis"), we identified and reviewed 153 unique Web site hits for information quality and readability. Web sites were specifically analyzed by search term and Web site modality. Information quality was evaluated on a 5-point scale. Information readability was assessed using the Flesch-Kincaid score for reading grade level. Results The average quality score was low. The average reading grade level was nearly six grade levels above that recommended by National Work Group on Literacy and Health. The quality and readability of Internet information was significantly dependent on Web site modality. The use of more complex search terms yielded information of higher reading grade level but not higher quality. Conclusions Higher-quality information about lumbar fusion conveyed using language that is more readable by the general public is needed on the Internet. It is important for health care providers to be aware of the information accessible to patients, as it likely influences their decision making regarding care.

Evidence of parasexual activity in "asexual amoebae" Cochliopodium spp. (Amoebozoa): extensive cellular and nuclear fusion.

PubMed

Tekle, Yonas I; Anderson, O Roger; Lecky, Ariel F

2014-09-01

The majority of microbial eukaryotes have long been considered asexual, though new evidence indicates sex, or sexual-like (parasexual) behaviors that deviate from the usual union of two gametes, among other variant aspects. Over a dozen amoebozoans are implicated to have sexual stages. However, the exact mechanism by which sex occurs in these lineages remains elusive. This is mainly due to the diverse quality and cryptic nature of their life cycle. In this study we present evidence of some previously unreported aspects of the life cycle of an amoeba, Cochliopodium, that undergoes unusual intraspecific interactions using light microscopy and immunocytochemistry. Similar to other amoebozoans, Cochliopodium, is considered asexual with no published reports of sex or parasexuality. We also investigated environmental conditions that govern the observed intraspecific interactions. Both light microscopic and immunocytochemistry evidence demonstrates Cochliopodium undergoes cellular fusion (plasmogamy) and nuclear fusion (karyogamy). Large plasmodia eventually undergo karyogamy and contain large fused, polyploid, nuclei. These are observed to fragment, subsequently, by karyotomy (nuclear fission) and cytoplasmic fission to yield uninucleated amoebae. This process could lead to a non-meiotic, parasexual exchange of chromosomes in Cochliopodium. These findings strongly suggest that Cochliopodium is involved in parasexual activity and should no longer be considered strictly asexual. Copyright © 2014 Elsevier GmbH. All rights reserved.

Delayed childbearing: determining responsibilities for prime gamete quality.

PubMed

Campagne, Daniel M

2013-01-01

Delayed parenting affects fertility in women and in men, and cryopreservation of oocytes and sperm is becoming the latest trend as a solution for those who want or need to postpone procreation, in an attempt to avoid the damage medical conditions or time itself produces in gametes. Although "social freezing" is considered legitimate, its ethical and social aspects are in need of an overdue medical, public and legal debate. Assisted reproduction and cryopreservation, in combination with womb outsourcing, have opened the door to biological ectogenesis and the subsequent question of whether delayed childbearing means we should formally separate procreation from sexual activity. This article briefly summarizes what cryotechniques are capable of presently and in the near future, to separate fact from fiction. It names the implications for and discusses the practically virgin subject of the underlying responsibilities of delayed parenting techniques towards the child-to-be-not only the unborn but also the not-yet-conceived child. Considering the medical, economic, legal and social consequences of these rapidly growing developments in reproduction, several reasons point at the need to formally separate procreation from sexual activity, specifying responsibilities in the first while respecting personal choice in the second.

Reproductive and therapeutic cloning, germline therapy, and purchase of gametes and embryos: comments on Canadian legislation governing reproduction technologies

PubMed Central

Bernier, L; Gregoire, D

2004-01-01

In this article the three main topics covered in the new legislation are commented on: cloning, germline therapy, and purchase of gametes and embryos. Some important issues also covered in the new legislation, such as privacy and access to information, data protection, identity of donors, and inspection, will not be addressed. PMID:15574437

Collection of gametes from live axolotl, Ambystoma mexicanum, and standardization of in vitro fertilization.

PubMed

Mansour, N; Lahnsteiner, F; Patzner, R A

2011-01-15

This study established the first protocol for collection of gametes from live axolotl, Ambystoma mexicanum, by gentle abdominal massage and in vitro fertilization. To stimulate spermiation and ovulation, human chorionic gonadotrophin (hCG) and Ovopel pellets, which are commercially used to stimulate spawning in fish, were tested. The hCG was more effective than Ovopel pellets and yielded a higher semen volume in the injected males and a shorter response time in the females. Collected semen by this method was already motile and fertile. Fertile eggs could be collected in 3-4 successive collection times after the female has started the typical spawning behaviour. The fertilization condition that yielded the highest hatching rate was mixing semen with eggs before the addition of a fertilization saline solution (20 mmol/l NaCl, 1 mmol/l KCl, 1 mmol/l Mg(2)SO(4), 1 mmol Ca(2)Cl, 3 mmol NaHCO(3), 10 mmol/l Tris, pH 8.5 - Osmolality = 65 mosmol/kg). When the pH of the fertilization solution was increased to ≥ 10, the hatching rate was significantly increased. The use of fertilization solutions with osmolalities of ≥ 150 and ≥ 182 were accompanied with a significant decrease in hatching rates and the appearance of deformed larvae, respectively. In conclusion, a reliable protocol for gamete collection from live axolotl is established as a laboratory model of in vitro fertilization for urodele amphibians. This protocol may be transferable to endangered urodeles. Copyright © 2011 Elsevier Inc. All rights reserved.

Mechanism of Fusion Triggering by Human Parainfluenza Virus Type III

PubMed Central

Porotto, Matteo; Palmer, Samantha G.; Palermo, Laura M.; Moscona, Anne

2012-01-01

Parainfluenza viruses enter host cells by fusing the viral and target cell membranes via concerted action of their two envelope glycoproteins: the hemagglutinin-neuraminidase (HN) and the fusion protein (F). Receptor-bound HN triggers F to undergo conformational changes that render it fusion-competent. To address the role of receptor engagement and to elucidate how HN and F interact during the fusion process, we used bimolecular fluorescence complementation to follow the dynamics of human parainfluenza virus type 3 (HPIV3) HN/F pairs in living cells. We show that HN and F associate before receptor engagement. HN drives the formation of HN-F clusters at the site of fusion, and alterations in HN-F interaction determine the fusogenicity of the glycoprotein pair. An interactive site, at the HN dimer interface modulates HN fusion activation property, which is critical for infection of the natural host. This first evidence for the sequence of initial events that lead to viral entry may indicate a new paradigm for understanding Paramyxovirus infection. PMID:22110138

Polyclonal and monoclonal antibodies specific for the six-helix bundle of the human respiratory syncytial virus fusion glycoprotein as probes of the protein post-fusion conformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palomo, Concepción; Mas, Vicente; Vázquez, Mónica

Human respiratory syncytial virus (hRSV) has two major surface glycoproteins (G and F) anchored in the lipid envelope. Membrane fusion promoted by hRSV{sub F} occurs via refolding from a pre-fusion form to a highly stable post-fusion state involving large conformational changes of the F trimer. One of these changes results in assembly of two heptad repeat sequences (HRA and HRB) into a six-helix bundle (6HB) motif. To assist in distinguishing pre- and post-fusion conformations of hRSV{sub F}, we have prepared polyclonal (α-6HB) and monoclonal (R145) rabbit antibodies specific for the 6HB. Among other applications, these antibodies were used to exploremore » the requirements of 6HB formation by isolated protein segments or peptides and by truncated mutants of the F protein. Site-directed mutagenesis and electron microscopy located the R145 epitope in the post-fusion hRSV{sub F} at a site distantly located from previously mapped epitopes, extending the repertoire of antibodies that can decorate the F molecule. - Highlights: • Antibodies specific for post-fusion respiratory syncytial virus fusion protein are described. • Polyclonal antibodies were obtained in rabbit inoculated with chimeric heptad repeats. • Antibody binding required assembly of a six-helix bundle in the post-fusion protein. • A monoclonal antibody with similar structural requirements is also described. • Binding of this antibody to the post-fusion protein was visualized by electron microscopy.« less

Flow and transport model of the Savannah River Site Old Burial Grounds using Data Fusion modeling (DFM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-11-01

The Data Fusion Modeling (DFM) approach has been used to develop a groundwater flow and transport model of the Old Burial Grounds (OBG) at the US Department of Energy`s Savannah River Site (SRS). The resulting DFM model was compared to an existing model that was calibrated via the typical trial-and-error method. The OBG was chosen because a substantial amount of hydrogeologic information is available, a FACT (derivative of VAM3DCG) flow and transport model of the site exists, and the calibration and numerics were challenging with standard approaches. The DFM flow model developed here is similar to the flow model bymore » Flach et al. This allows comparison of the two flow models and validates the utility of DFM. The contaminant of interest for this study is tritium, because it is a geochemically conservative tracer that has been monitored along the seepline near the F-Area effluent and Fourmile Branch for several years.« less

Two HAP2-GCS1 homologs responsible for gamete interactions in the cellular slime mold with multiple mating types: Implication for common mechanisms of sexual reproduction shared by plants and protozoa and for male-female differentiation.

PubMed

Okamoto, Marina; Yamada, Lixy; Fujisaki, Yukie; Bloomfield, Gareth; Yoshida, Kentaro; Kuwayama, Hidekazu; Sawada, Hitoshi; Mori, Toshiyuki; Urushihara, Hideko

2016-07-01

Fertilization is a central event in sexual reproduction, and understanding its molecular mechanisms has both basic and applicative biological importance. Recent studies have uncovered the molecules that mediate this process in a variety of organisms, making it intriguing to consider conservation and evolution of the mechanisms of sexual reproduction across phyla. The social amoeba Dictyostelium discoideum undergoes sexual maturation and forms gametes under dark and humid conditions. It exhibits three mating types, type-I, -II, and -III, for the heterothallic mating system. Based on proteome analyses of the gamete membranes, we detected expression of two homologs of the plant fertilization protein HAP2-GCS1. When their coding genes were disrupted in type-I and type-II strains, sexual potency was completely lost, whereas disruption in the type-III strain did not affect mating behavior, suggesting that the latter acts as female in complex organisms. Our results demonstrate the highly conserved function of HAP2-GCS1 in gamete interactions and suggest the presence of additional allo-recognition mechanisms in D. discoideum gametes. Copyright © 2016 Elsevier Inc. All rights reserved.

Examination of relaxin and its receptors expression in pig gametes and embryos

PubMed Central

2011-01-01

Background Relaxin is a small peptide also known as pregnancy hormone in many mammals. It is synthesized by both male and female tissues, and its secretions are found in various body fluids such as plasma serum, ovarian follicular fluid, utero-oviduct secretions, and seminal plasma of many mammals, including pigs. However, the presence and effects of relaxin in porcine gametes and embryos are still not well-known. The purpose of this study was to assess the presence of relaxin and its receptors RXFP1 and RXFP2 in pig gametes and embryos. Methods Immature cumulus-oocyte complexes (COCs) were aspirated from sows' ovaries collected at the abattoir. After in vitro-maturation, COCs were in vitro-fertilized and cultured. For studies, immature and mature COCs were separately collected, and oocytes were freed from their surrounding cumulus cells. Denuded oocytes, cumulus cells, mature boar spermatozoa, zygotes, and embryos (cleaved and blastocysts) were harvested for temporal and spatial gene expression studies. Sections of ovary, granulosa and neonatal porcine uterine cells were also collected to use as controls. Results Using both semi-quantitative and quantitative PCRs, relaxin transcripts were not detected in all tested samples, while RXFP1 and RXFP2 mRNA were present. Both receptor gene products were found at higher levels in oocytes compared to cumulus cells, irrespective of the maturation time. Cleaved-embryos contained higher levels of RXFP2 mRNA, whereas, blastocysts were characterized by a higher RXFP1 mRNA content. Using western-immunoblotting or in situ immunofluorescence, relaxin and its receptor proteins were detected in all samples. Their fluorescence intensities were consistently more important in mature oocytes than immature ones. The RXFP1 and RXFP2 signal intensities were mostly located in the plasma membrane region, while the relaxin ones appeared homogeneously distributed within the oocytes and embryonic cells. Furthermore, spermatozoa displayed

An Injectable Method for Posterior Lateral Spine Fusion

DTIC Science & Technology

2015-09-01

hours later infected cells were identified using a rapid titer kit. As expected the sera from animals that received PBS had similar infectious...the site of HO is active. Additionally, we confirmed that the lack of bone formation after delivery of the microspheres to larger animal models...matrix remodeling and fusion. Therefore we have secured animal approval for the studies, and performed spine fusion in mice to generate tissue

Fusions within the mandible of the domestic fowl (Gallus gallus domesticus).

PubMed Central

Hogg, D A

1983-01-01

The articulations formed within the mandible of the domestic fowl by its constituent elements have been described and illustrated. The sutures identified were suturae angulosplenialis, angulosupra-angularis, articulare/pre-articulo-angularis, articulare/pre-articulosupra-angularis, dento-angularis, dentosplenialis, dentosupra-angularis and supra-angulosplenialis. Some degree of fusion was found to occur in all sutures except sutura supra-angulosplenialis. The range of fusion time and mean fusion time for each site was studied in a flock of Golden Comet pullets. Mean fusion times varied from 45-119 days post-hatching. PMID:6885616

Fusions within the mandible of the domestic fowl (Gallus gallus domesticus).

PubMed

Hogg, D A

1983-05-01

The articulations formed within the mandible of the domestic fowl by its constituent elements have been described and illustrated. The sutures identified were suturae angulosplenialis, angulosupra-angularis, articulare/pre-articulo-angularis, articulare/pre-articulosupra-angularis, dento-angularis, dentosplenialis, dentosupra-angularis and supra-angulosplenialis. Some degree of fusion was found to occur in all sutures except sutura supra-angulosplenialis. The range of fusion time and mean fusion time for each site was studied in a flock of Golden Comet pullets. Mean fusion times varied from 45-119 days post-hatching.

Evaluation of Parameters for Confident Phosphorylation Site Localization Using an Orbitrap Fusion Tribrid Mass Spectrometer.

PubMed

Ferries, Samantha; Perkins, Simon; Brownridge, Philip J; Campbell, Amy; Eyers, Patrick A; Jones, Andrew R; Eyers, Claire E

2017-09-01

Confident identification of sites of protein phosphorylation by mass spectrometry (MS) is essential to advance understanding of phosphorylation-mediated signaling events. However, the development of novel instrumentation requires that methods for MS data acquisition and its interrogation be evaluated and optimized for high-throughput phosphoproteomics. Here we compare and contrast eight MS acquisition methods on the novel tribrid Orbitrap Fusion MS platform using both a synthetic phosphopeptide library and a complex phosphopeptide-enriched cell lysate. In addition to evaluating multiple fragmentation regimes (HCD, EThcD, and neutral-loss-triggered ET(ca/hc)D) and analyzers for MS/MS (orbitrap (OT) versus ion trap (IT)), we also compare two commonly used bioinformatics platforms, Andromeda with PTM-score, and MASCOT with ptmRS for confident phosphopeptide identification and, crucially, phosphosite localization. Our findings demonstrate that optimal phosphosite identification is achieved using HCD fragmentation and high-resolution orbitrap-based MS/MS analysis, employing MASCOT/ptmRS for data interrogation. Although EThcD is optimal for confident site localization for a given PSM, the increased duty cycle compared with HCD compromises the numbers of phosphosites identified. Finally, our data highlight that a charge-state-dependent fragmentation regime and a multiple algorithm search strategy are likely to be of benefit for confident large-scale phosphosite localization.

The ubiquitin–proteasome system regulates membrane fusion of yeast vacuoles

PubMed Central

Kleijnen, Maurits F; Kirkpatrick, Donald S; Gygi, Steven P

2007-01-01

Ubiquitination is known to regulate early stages of intracellular vesicular transport, without proteasomal involvement. We now show that, in yeast, ubiquitination regulates a late-stage, membrane fusion, with proteasomal involvement. A known proteasome mutant had a vacuolar fragmentation phenotype in vivo often associated with vacuolar membrane fusion defects, suggesting a proteasomal role in fusion. Inhibiting vacuolar proteasomes interfered with membrane fusion in vitro, showing that fusion cannot occur without proteasomal degradation. If so, one would expect to find ubiquitinated proteins on vacuolar membranes. We found a small number of these, identified the most prevalent one as Ypt7 and mapped its two major ubiquitination sites. Ubiquitinated Ypt7 was linked to the degradation event that is necessary for fusion: vacuolar Ypt7 and vacuolar proteasomes were interdependent, ubiquitinated Ypt7 became a proteasomal substrate during fusion, and proteasome inhibitors reduced fusion to greater degree when we decreased Ypt7 ubiquitination. The strongest model holds that fusion cannot proceed without proteasomal degradation of ubiquitinated Ypt7. As Ypt7 is one of many Rab GTPases, ubiquitin–proteasome regulation may be involved in membrane fusion elsewhere. PMID:17183369

Recent speciation in the Indo-West Pacific: rapid evolution of gamete recognition and sperm morphology in cryptic species of sea urchin.

PubMed Central

Landry, C; Geyer, L B; Arakaki, Y; Uehara, T; Palumbi, Stephen R

2003-01-01

The rich species diversity of the marine Indo-West Pacific (IWP) has been explained largely on the basis of historical observation of large-scale diversity gradients. Careful study of divergence among closely related species can reveal important new information about the pace and mechanisms of their formation, and can illuminate the genesis of biogeographic patterns. Young species inhabiting the IWP include urchins of the genus Echinometra, which diverged over the past 1-5 Myr. Here, we report the most recent divergence of two cryptic species of Echinometra inhabiting this region. Mitochondrial cytochrome oxidase 1 (CO1) sequence data show that in Echinometra oblonga, species-level divergence in sperm morphology, gamete recognition proteins and gamete compatibility arose between central and western Pacific populations in the past 250 000 years. Divergence in sperm attachment proteins suggests rapid evolution of the fertilization system. Divergence of sperm morphology may be a common feature of free-spawning animals, and offers opportunities to simultaneously understand genetic divergence, changes in protein expression patterns and morphological evolution in traits directly related to reproductive isolation. PMID:12964987

A novel protocol for the production of recombinant LL-37 expressed as a thioredoxin fusion protein.

PubMed

Li, Yifeng

2012-02-01

LL-37 is the only cathelicidin-derived antimicrobial peptide found in humans and it has a multifunctional role in host defense. The peptide has been shown to possess immunomodulatory functions in addition to antimicrobial activity. To provide sufficient material for biological and structural characterization of this important peptide, various systems were developed to produce recombinant LL-37 in Escherichia coli. In one previous approach, LL-37 coding sequence was cloned into vector pET-32a, allowing the peptide to be expressed as a thioredoxin fusion. The fusion protein contains two thrombin cleavage sites: a vector-encoded one that is 30-residue upstream of the insert and an engineered one that is immediately adjacent to LL-37. Cleavage at these two sites shall generate three fragments, one of which is the target peptide. However, when the fusion protein was treated with thrombin, cleavage only occurred at the remote upstream site. A plausible explanation is that the thrombin site adjacent to LL-37 is less accessible due to the peptide's aggregation tendency and cleavage at the remote site generates a fragment, which forms a large aggregate that buries the intended site. In this study, I deleted the vector-encoded thrombin site and S tag in pET-32a, and then inserted the coding sequence for LL-37 plus a thrombin site into the modified vector. Although removing the S tag did not change the oligomeric state of the fusion protein, deletion of the vector-encoded thrombin site allowed the fusion to be cleaved at the engineered site to release LL-37. The released peptide was separated from the carrier and cleavage enzyme by size-exclusion chromatography. This new approach enables a quick production of high quality active LL-37 with a decent amount. Copyright © 2011 Elsevier Inc. All rights reserved.

Antibody-cytokine fusion proteins for improving efficacy and safety of cancer therapy.

PubMed

Valedkarimi, Zahra; Nasiri, Hadi; Aghebati-Maleki, Leili; Majidi, Jafar

2017-11-01

Cytokines are key players in the regulation of immune responses both in physiological and pathological states. A number of cytokines have been evaluated in clinical trials and shown promising results in the treatment of different malignancies. Despite this, the clinical application of these molecules may be plagued by undesirable side effects The development of recombinant antibody-cytokine fusion proteins, which offer a means for target delivery of cytokines toward the tumor site, has significantly improved the therapeutic index of these immunomodulatory molecules. Selective tumor localization is provided by the monoclonal antibody component of the fusion protein that binds to the molecules present on the surface of tumor cells or accumulated preferentially in the diseased site. In this manner, the cytokine element is specifically located at the tumor site and can stimulate immune cells with appropriate cytokine receptors. Over the recent years, several antibody-cytokine fusion proteins have been developed with the capacity to target a wide variety of cancers whose application, in some cases, has led to complete rejection of the tumor. These findings support the notion that antibody-cytokine fusion proteins represent huge potential for cancer therapy. This review presents an overview of the advances made in the field of targeted cytokine delivery, which is made possible by genetically engineering antibody-cytokine fusion proteins. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Nuclear fusion during yeast mating occurs by a three-step pathway.

PubMed

Melloy, Patricia; Shen, Shu; White, Erin; McIntosh, J Richard; Rose, Mark D

2007-11-19

In Saccharomyces cerevisiae, mating culminates in nuclear fusion to produce a diploid zygote. Two models for nuclear fusion have been proposed: a one-step model in which the outer and inner nuclear membranes and the spindle pole bodies (SPBs) fuse simultaneously and a three-step model in which the three events occur separately. To differentiate between these models, we used electron tomography and time-lapse light microscopy of early stage wild-type zygotes. We observe two distinct SPBs in approximately 80% of zygotes that contain fused nuclei, whereas we only see fused or partially fused SPBs in zygotes in which the site of nuclear envelope (NE) fusion is already dilated. This demonstrates that SPB fusion occurs after NE fusion. Time-lapse microscopy of zygotes containing fluorescent protein tags that localize to either the NE lumen or the nucleoplasm demonstrates that outer membrane fusion precedes inner membrane fusion. We conclude that nuclear fusion occurs by a three-step pathway.

The effect of mental illness and psychotropic medication on gametes and fertility: a systematic review.

PubMed

Worly, Brett L; Gur, Tamar L

2015-07-01

Psychiatric disorders during the reproductive years and their treatment with psychotropic medications are increasingly common, and their effect on the reproductive system is an important area of research. To review the effect of mental illness and psychotropic medication on gametes and fertility. Searches of the PubMed database were conducted for English-language articles containing the keywords gametes, fertility, psychotropic, oocyte, sperm, mental illness, depression, and/or anxiety, in the title or abstract. The searches yielded 3,603 citations. Studies were evaluated for relevance. Those not pertinent to the clinical question, not written in English, and focusing on invertebrates were excluded. Full texts of 50 articles were obtained for further evaluation. Additional articles were identified from reference lists. Ultimately, a total of 37 studies were deemed suitable and reviewed. Clinical studies have not demonstrated a deleterious effect of psychotropic medication on oocytes in terms of retrieval and pregnancy rates. Clinical studies demonstrate inconclusive results regarding the effect on sperm, with several studies suggesting increased sperm motility and quantity with certain psychotropics. Decreased sperm quantity and motility are described in a number of studies, including in vitro and in vivo studies. Maternal psychiatric illness is associated with decreased reproductive success, including lower rates of oocyte retrieval, lower rates of ongoing pregnancy, and dysregulation of the stress system in a majority (n = 11) but not all (n = 3) studies reviewed. Male depression did not appear to affect sperm, but anxiety did have an effect (n = 1). Given the detrimental effect of untreated mental illness, current literature is not robust enough to influence the use of psychotropics in males or females who are considering reproduction. © Copyright 2015 Physicians Postgraduate Press, Inc.

ESHRE Task Force on Ethics and Law 21: genetic screening of gamete donors: ethical issues.

PubMed

Dondorp, W; De Wert, G; Pennings, G; Shenfield, F; Devroey, P; Tarlatzis, B; Barri, P; Diedrich, K; Eichenlaub-Ritter, U; Tüttelmann, F; Provoost, V

2014-07-01

This Task Force document explores the ethical issues involved in the debate about the scope of genetic screening of gamete donors. Calls for expanded donor screening arise against the background of both occasional findings of serious but rare genetic conditions in donors or donor offspring that were not detected through present screening procedures and the advent of new genomic technologies promising affordable testing of donors for a wide range of conditions. Ethical principles require that all stakeholders' interests are taken into account, including those of candidate donors. The message of the profession should be that avoiding all risks is impossible and that testing should remain proportional.

To give or sell human gametes - the interplay between pragmatics, policy and ethics

PubMed Central

Daniels, K

2000-01-01

The ever-growing acceptance and use of assisted human reproduction techniques has caused demand for "donated" sperm and eggs to outstrip supply. Medical professionals and others argue that monetary reward is the only way to recruit sufficient numbers of "donors". Is this a clash between pragmatics and policy/ethics? Where monetary payments are the norm, alternative recruitment strategies used successfully elsewhere may not have been considered, nor the negative consequences of commercialism on all participants thought through. Considerations leading some countries to ban the buying and selling of sperm, eggs and embryos are outlined and a case made that the collective welfare of all involved parties be the primary consideration in this, at times heated, debate. Key Words: Gametes • gifting • selling • ethics • policy PMID:10860215

Myosin heavy chain-like localizes at cell contact sites during Drosophila myoblast fusion and interacts in vitro with Rolling pebbles 7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonn, Bettina R.; Rudolf, Anja; Hornbruch-Freitag, Christina

2013-02-15

Besides representing the sarcomeric thick filaments, myosins are involved in many cellular transport and motility processes. Myosin heavy chains are grouped into 18 classes. Here we show that in Drosophila, the unconventional group XVIII myosin heavy chain-like (Mhcl) is transcribed in the mesoderm of embryos, most prominently in founder cells (FCs). An ectopically expressed GFP-tagged Mhcl localizes in the growing muscle at cell–cell contacts towards the attached fusion competent myoblast (FCM). We further show that Mhcl interacts in vitro with the essential fusion protein Rolling pebbles 7 (Rols7), which is part of a protein complex established at cell contact sitesmore » (Fusion-restricted Myogenic-Adhesive Structure or FuRMAS). Here, branched F-actin is likely needed to widen the fusion pore and to integrate the myoblast into the growing muscle. We show that the localization of Mhcl is dependent on the presence of Rols7, and we postulate that Mhcl acts at the FuRMAS as an actin motor protein. We further show that Mhcl deficient embryos develop a wild-type musculature. We thus propose that Mhcl functions redundantly to other myosin heavy chains in myoblasts. Lastly, we found that the protein is detectable adjacent to the sarcomeric Z-discs, suggesting an additional function in mature muscles. - Highlights: ► The class XVIII myosin encoding gene Mhcl is transcribed in the mesoderm. ► Mhcl localization at contact sites of fusing myoblasts depends on Rols7. ► Mhcl interacts in vitro with Rols7 which is essential for myogenesis. ► Functional redundancy with other myosins is likely as mutants show no muscle defects. ► Mhcl localizes adjacent to Z-discs of sarcomeres and might support muscle integrity.« less

Multimerized CHR-derived peptides as HIV-1 fusion inhibitors.

PubMed

Nomura, Wataru; Hashimoto, Chie; Suzuki, Takaharu; Ohashi, Nami; Fujino, Masayuki; Murakami, Tsutomu; Yamamoto, Naoki; Tamamura, Hirokazu

2013-08-01

To date, several HIV-1 fusion inhibitors based on the carboxy-terminal leucine/isoleucine heptad repeat (CHR) region of an HIV-1 envelope protein gp41 have been discovered. We have shown that a synthetic peptide mimetic of a trimer form of the CHR-derived peptide C34 has potent inhibitory activity against the HIV-1 fusion mechanism, compared to a monomer C34 peptide. The present study revealed that a dimeric form of C34 is evidently structurally critical for fusion inhibitors, and that the activity of multimerized CHR-derived peptides in fusion inhibition is affected by the properties of the unit peptides C34, SC34EK, and T20. The fluorescence-based study suggested that the N36-interactive sites of the C34 trimer, including hydrophobic residues, are exposed outside the trimer and that trimerization of C34 caused a remarkable increase in fusion inhibitory activity. The present results could be useful in the design of fusion inhibitors against viral infections which proceed via membrane fusion with host cells. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Normal myoblast fusion requires myoferlin

PubMed Central

Doherty, Katherine R.; Cave, Andrew; Davis, Dawn Belt; Delmonte, Anthony J.; Posey, Avery; Earley, Judy U.; Hadhazy, Michele; McNally, Elizabeth M.

2014-01-01

Summary Muscle growth occurs during embryonic development and continues in adult life as regeneration. During embryonic muscle growth and regeneration in mature muscle, singly nucleated myoblasts fuse to each other to form myotubes. In muscle growth, singly nucleated myoblasts can also fuse to existing large, syncytial myofibers as a mechanism of increasing muscle mass without increasing myofiber number. Myoblast fusion requires the alignment and fusion of two apposed lipid bilayers. The repair of muscle plasma membrane disruptions also relies on the fusion of two apposed lipid bilayers. The protein dysferlin, the product of the Limb Girdle Muscular Dystrophy type 2 locus, has been shown to be necessary for efficient, calcium-sensitive, membrane resealing. We now show that the related protein myoferlin is highly expressed in myoblasts undergoing fusion, and is expressed at the site of myoblasts fusing to myotubes. Like dysferlin, we found that myoferlin binds phospholipids in a calcium-sensitive manner that requires the first C2A domain. We generated mice with a null allele of myoferlin. Myoferlin null myoblasts undergo initial fusion events, but they form large myotubes less efficiently in vitro, consistent with a defect in a later stage of myogenesis. In vivo, myoferlin null mice have smaller muscles than controls do, and myoferlin null muscle lacks large diameter myofibers. Additionally, myoferlin null muscle does not regenerate as well as wild-type muscle does, and instead displays a dystrophic phenotype. These data support a role for myoferlin in the maturation of myotubes and the formation of large myotubes that arise from the fusion of myoblasts to multinucleate myotubes. PMID:16280346

Fusion 2.0: The Next Generation of Fusion in California: Aligning State and Regional Fusion Centers

DTIC Science & Technology

2010-03-01

bible ” for fusion center management, as evidenced by the theme of the 2009 National Fusion Center Conference; appropriately called “Achieving Baseline...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS FUSION 2.0: THE NEXT GENERATION OF FUSION IN CALIFORNIA: ALIGNING STATE AND...Master’s Thesis 4. TITLE AND SUBTITLE Fusion 2.0: The Next Generation of Fusion in California: Aligning State and Regional Fusion

HIV-1 virion fusion assay: uncoating not required and no effect of Nef on fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cavrois, Marielle; Neidleman, Jason; Yonemoto, Wes

2004-10-15

We recently described a sensitive and specific assay that detects the fusion of HIV-1 virions to a broad range of target cells, including primary CD4 cells. This assay involves the use of virions containing {beta}-lactamase-Vpr (BlaM-Vpr) and the loading of target cells with CCF2, a fluorogenic substrate of {beta}-lactamase. Since Vpr strongly associates with the viral core, uncoating of the viral particle might be required for effective cleavage of CCF2 by BlaM-Vpr. Here, we show that BlaM-Vpr within mature viral cores effectively cleaves CCF2, indicating that this assay measures virion fusion independently of uncoating. We also show that wildtype andmore » Nef-deficient HIV-1 virions fuse with equivalent efficiency to HeLa-CD4 cells, SupT1 T cells, and primary CD4 T cells. Since Nef enhances cytoplasmic delivery of viral cores and increases viral infectivity, these findings indicate that Nef enhances an early post-fusion event in the multistep process of viral entry. Possible sites of Nef action include enlargement of the fusion pore, enhanced uncoating of viral particles, and more efficient passage of viral cores through the dense cortical actin network located immediately beneath the plasma membrane.« less

Two O-linked N-acetylglucosamine transferase genes of Arabidopsis thaliana L. Heynh. have overlapping functions necessary for gamete and seed development.

PubMed Central

Hartweck, Lynn M; Scott, Cheryl L; Olszewski, Neil E

2002-01-01

The Arabidopsis SECRET AGENT (SEC) and SPINDLY (SPY) proteins are similar to animal O-linked N-acetylglucosamine transferases (OGTs). OGTs catalyze the transfer of N-acetylglucosamine (GlcNAc) from UDP-GlcNAc to Ser/Thr residues of proteins. In animals, O-GlcNAcylation has been shown to affect protein activity, stability, and/or localization. SEC protein expressed in Escherichia coli had autocatalytic OGT activity. To determine the function of SEC in plants, two tDNA insertional mutants were identified and analyzed. Although sec mutant plants did not exhibit obvious phenotypes, sec and spy mutations had a synthetic lethal interaction. This lethality was incompletely penetrant in gametes and completely penetrant postfertilization. The rate of both female and male sec spy gamete transmission was higher in plants heterozygous for both mutations than in plants heterozygous for sec and homozygous for spy. Double-mutant embryos aborted at various stages of development and no double-mutant seedlings were obtained. These results indicate that OGT activity is required during gametogenesis and embryogenesis with lethality occurring when parentally derived SEC, SPY, and/or O-GlcNAcylated proteins become limiting. PMID:12136030

Detecting Coevolution in Mammalian Sperm–Egg Fusion Proteins

PubMed Central

CLAW, KATRINA G.; GEORGE, RENEE D.; SWANSON, WILLIE J.

2018-01-01

SUMMARY Interactions between sperm and egg proteins can occur physically between gamete surface-binding proteins, and genetically between gamete proteins that work in complementary pathways in which they may not physically interact. Physically interacting sperm–egg proteins have been functionally identified in only a few species, and none have been verified within mammals. Candidate genes on both the sperm and egg surfaces exist, but gene deletion studies do not support functional interactions between these sperm–egg proteins; interacting sperm–egg proteins thus remain elusive. Cooperative gamete proteins undergo rapid evolution, and it is predicted that these sperm–egg proteins will also have correlated evolutionary rates due to compensatory changes on both the sperm and egg. To explore potential physical and genetic interactions in sperm–egg proteins, we sequenced four candidate genes from diverse primate species, and used regression and likelihood methods to test for signatures of coevolution between sperm–egg gene pairs. With both methods, we found that the egg protein CD9 coevolves with the sperm protein IZUMO1, suggesting a physical or genetic interaction occurs between them. With regression analysis, we found that CD9 and CRISP2 have correlated rates of evolution, and with likelihood analysis, that CD9 and CRISP1 have correlated rates. This suggests that the different tests may reflect different levels of interaction, be it physical or genetic. Coevolution tests thus provide an exploratory method for detecting potentially interacting sperm–egg protein pairs. PMID:24644026

Detecting coevolution in mammalian sperm-egg fusion proteins.

PubMed

Claw, Katrina G; George, Renee D; Swanson, Willie J

2014-06-01

Interactions between sperm and egg proteins can occur physically between gamete surface-binding proteins, and genetically between gamete proteins that work in complementary pathways in which they may not physically interact. Physically interacting sperm-egg proteins have been functionally identified in only a few species, and none have been verified within mammals. Candidate genes on both the sperm and egg surfaces exist, but gene deletion studies do not support functional interactions between these sperm-egg proteins; interacting sperm-egg proteins thus remain elusive. Cooperative gamete proteins undergo rapid evolution, and it is predicted that these sperm-egg proteins will also have correlated evolutionary rates due to compensatory changes on both the sperm and egg. To explore potential physical and genetic interactions in sperm-egg proteins, we sequenced four candidate genes from diverse primate species, and used regression and likelihood methods to test for signatures of coevolution between sperm-egg gene pairs. With both methods, we found that the egg protein CD9 coevolves with the sperm protein IZUMO1, suggesting a physical or genetic interaction occurs between them. With regression analysis, we found that CD9 and CRISP2 have correlated rates of evolution, and with likelihood analysis, that CD9 and CRISP1 have correlated rates. This suggests that the different tests may reflect different levels of interaction, be it physical or genetic. Coevolution tests thus provide an exploratory method for detecting potentially interacting sperm-egg protein pairs. © 2014 Wiley Periodicals, Inc.

Autograft versus Allograft for Cervical Spinal Fusion

PubMed Central

Brodke, Darrel S.; Youssef, Jim A.; Meisel, Hans-Jörg; Dettori, Joseph R.; Park, Jong-Beom; Yoon, S. Tim; Wang, Jeffrey C.

2017-01-01

Study Design Systematic review. Objective To compare the effectiveness and safety between iliac crest bone graft (ICBG), non-ICBG autologous bone, and allograft in cervical spine fusion. To avoid problems at the donor site, various allograft materials have been used as a substitute for autograft. However, there are still questions as to the comparative effectiveness and safety of cadaver allograft compared with autologous ICBG. Methods A systematic search of multiple major medical reference databases was conducted to identify studies evaluating spinal fusion in patients with cervical degenerative disk disease using ICBG compared with non-ICBG autograft or allograft or non-ICBG autograft compared with allograft in the cervical spine. Radiographic fusion, patient-reported outcomes, and functional outcomes were the primary outcomes of interest. Adverse events were evaluated for safety. Results The search identified 13 comparative studies that met our inclusion criteria: 2 prospective cohort studies and 11 retrospective cohort studies. Twelve cohort studies compared allograft with ICBG autograft during anterior cervical fusion and demonstrated with a low evidence level of support that there are no differences in fusion percentages, pain scores, or functional results. There was insufficient evidence comparing patients receiving allograft with non-ICBG autograft for fusion, pain, revision, and functional and safety outcomes. No publications directly comparing non-ICBG autograft with ICBG were found. Conclusion Although the available literature suggests ICBG and allograft may have similar effectiveness in terms of fusion rates, pain scores, and functional outcomes following anterior cervical fusion, there are too many limitations in the available literature to draw any significant conclusions. No individual study provided greater than class III evidence, and when evaluating the overall body of literature, no conclusion had better than low evidence support. A prospective

Iliac Crest Bone Graft versus Local Autograft or Allograft for Lumbar Spinal Fusion: A Systematic Review.

PubMed

Tuchman, Alexander; Brodke, Darrel S; Youssef, Jim A; Meisel, Hans-Jörg; Dettori, Joseph R; Park, Jong-Beom; Yoon, S Tim; Wang, Jeffrey C

2016-09-01

Systematic review. To compare the effectiveness and safety between iliac crest bone graft (ICBG) and local autologous bone and allograft in the lumbar spine. A systematic search of multiple major medical reference databases identified studies evaluating spinal fusion in patients with degenerative joint disease using ICBG, local autograft, or allograft in the thoracolumbar spine. Six comparative studies met our inclusion criteria. A "low" strength of the overall body of evidence suggested no difference in fusion percentages in the lumbar spine between local autograft and ICBG. We found no difference in fusion percentages based on low evidence comparing allograft with ICBG autograft. There were no differences in pain or functional results comparing local autograft or allograft with ICBG autograft. Donor site pain and hematoma/seroma occurred more frequently in ICBG autograft group for lumbar fusion procedures. There was low evidence around the estimate of patients with donor site pain following ICBG harvesting, ranging from 16.7 to 20%. With respect to revision, low evidence demonstrated no difference between allograft and ICBG autograft. There was no evidence comparing patients receiving allograft with local autograft for fusion, pain, functional, and safety outcomes. In the lumbar spine, ICBG, local autograft, and allograft have similar effectiveness in terms of fusion rates, pain scores, and functional outcomes. However, ICBG is associated with an increased risk for donor site-related complications. Significant limitations exist in the available literature when comparing ICBG, local autograft, and allograft for lumbar fusion, and thus ICBG versus other fusion methods necessitates further investigation.

Direct current stimulation of titanium interbody fusion devices in primates.

PubMed

Cook, Stephen D; Patron, Laura P; Christakis, Petros M; Bailey, Kirk J; Banta, Charles; Glazer, Paul A

2004-01-01

The fusion rate for anterior lumbar interbody fusion (ALIF) varies widely with the use of different interbody devices and bone graft options. Adjunctive techniques such as electrical stimulation may improve the rate of bony fusion. To determine if direct current (DC) electrical stimulation of a metallic interbody fusion device enhanced the incidence or extent of anterior bony fusion. ALIF was performed using titanium alloy interbody fusion devices with and without adjunctive DC electrical stimulation in nonhuman primates. ALIF was performed through an anterolateral approach in 35 macaques with autogenous bone graft and either a titanium alloy (Ti-6Al-4V) fusion device or femoral allograft ring. The fusion devices of 19 animals received high (current density 19.6 microA/cm2) or low (current density 5.4 microA/cm2) DC electrical stimulation using an implanted generator for a 12- or 26-week evaluation period. Fusion sites were studied using serial radiographs, computed tomography imaging, nondestructive mechanical testing and qualitative and semiquantitative histology. Fusion was achieved with the titanium fusion device and autogenous bone graft. At 12 weeks, the graft was consolidating and early to moderate bridging callus was observed in and around the device. By 26 weeks, the anterior callus formation was more advanced with increased evidence of bridging trabeculations and early bone remodeling. The callus formation was not as advanced or abundant for the allograft ring group. Histology revealed the spinal fusion device had an 86% incidence of bony fusion at 26 weeks compared with a 50% fusion rate for the allograft rings. DC electrical stimulation of the fusion device had a positive effect on anterior interbody fusion by increasing both the presence and extent of bony fusion in a current density-dependent manner. Adjunctive DC electrical stimulation of the fusion device improved the rate and extent of bony fusion compared with a nonstimulated device. The fusion

Molecular mechanism of respiratory syncytial virus fusion inhibitors

DOE PAGES

Battles, Michael B.; Langedijk, Johannes P.; Furmanova-Hollenstein, Polina; ...

2015-12-07

Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. In this paper, we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitorsmore » or are involved in the conformational rearrangements required to accommodate inhibitor binding. Resistant viruses do not propagate as well as wild-type RSV in vitro, indicating a fitness cost for inhibitor escape. Finally and collectively, these findings provide new insight into class I viral fusion proteins and should facilitate development of optimal RSV fusion inhibitors.« less

Molecular mechanism of respiratory syncytial virus fusion inhibitors

PubMed Central

Battles, Michael B; Langedijk, Johannes P; Furmanova-Hollenstein, Polina; Chaiwatpongsakorn, Supranee; Costello, Heather M; Kwanten, Leen; Vranckx, Luc; Vink, Paul; Jaensch, Steffen; Jonckers, Tim H M; Koul, Anil; Arnoult, Eric; Peeples, Mark E; Roymans, Dirk; McLellan, Jason S

2016-01-01

Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitors or are involved in the conformational rearrangements required to accommodate inhibitor binding. Resistant viruses do not propagate as well as wild-type RSV in vitro, indicating a fitness cost for inhibitor escape. Collectively, these findings provide new insight into class I viral fusion proteins and should facilitate development of optimal RSV fusion inhibitors. PMID:26641933

The Armadillo Repeat Protein PF16 Is Essential for Flagellar Structure and Function in Plasmodium Male Gametes

PubMed Central

Ferguson, David J. P.; Bunting, Karen A.; Xu, Zhengyao; Bailes, Elizabeth; Sinden, Robert E.; Holder, Anthony A.; Smith, Elizabeth F.; Coates, Juliet C.; Rita Tewari

2010-01-01

Malaria, caused by the apicomplexan parasite Plasmodium, threatens 40% of the world's population. Transmission between vertebrate and insect hosts depends on the sexual stages of the life-cycle. The male gamete of Plasmodium parasite is the only developmental stage that possesses a flagellum. Very little is known about the identity or function of proteins in the parasite's flagellar biology. Here, we characterise a Plasmodium PF16 homologue using reverse genetics in the mouse malaria parasite Plasmodium berghei. PF16 is a conserved Armadillo-repeat protein that regulates flagellar structure and motility in organisms as diverse as green algae and mice. We show that P. berghei PF16 is expressed in the male gamete flagellum, where it plays a crucial role maintaining the correct microtubule structure in the central apparatus of the axoneme as studied by electron microscopy. Disruption of the PF16 gene results in abnormal flagellar movement and reduced fertility, but does not lead to complete sterility, unlike pf16 mutations in other organisms. Using homology modelling, bioinformatics analysis and complementation studies in Chlamydomonas, we show that some regions of the PF16 protein are highly conserved across all eukaryotes, whereas other regions may have species-specific functions. PF16 is the first ARM-repeat protein characterised in the malaria parasite genus Plasmodium and this study opens up a novel model for analysis of Plasmodium flagellar biology that may provide unique insights into an ancient organelle and suggest novel intervention strategies to control the malaria parasite. PMID:20886115

Tracking fusion of human mesenchymal stem cells after transplantation to the heart.

PubMed

Freeman, Brian T; Kouris, Nicholas A; Ogle, Brenda M

2015-06-01

Evidence suggests that transplanted mesenchymal stem cells (MSCs) can aid recovery of damaged myocardium caused by myocardial infarction. One possible mechanism for MSC-mediated recovery is reprogramming after cell fusion between transplanted MSCs and recipient cardiac cells. We used a Cre/LoxP-based luciferase reporter system coupled to biophotonic imaging to detect fusion of transplanted human pluripotent stem cell-derived MSCs to cells of organs of living mice. Human MSCs, with transient expression of a viral fusogen, were delivered to the murine heart via a collagen patch. At 2 days and 1 week later, living mice were probed for bioluminescence indicative of cell fusion. Cell fusion was detected at the site of delivery (heart) and in distal tissues (i.e., stomach, small intestine, liver). Fusion was confirmed at the cellular scale via fluorescence in situ hybridization for human-specific and mouse-specific centromeres. Human cells in organs distal to the heart were typically located near the vasculature, suggesting MSCs and perhaps MSC fusion products have the ability to migrate via the circulatory system to distal organs and engraft with local cells. The present study reveals previously unknown migratory patterns of delivered human MSCs and associated fusion products in the healthy murine heart. The study also sets the stage for follow-on studies to determine the functional effects of cell fusion in a model of myocardial damage or disease. Mesenchymal stem cells (MSCs) are transplanted to the heart, cartilage, and other tissues to recover lost function or at least limit overactive immune responses. Analysis of tissues after MSC transplantation shows evidence of fusion between MSCs and the cells of the recipient. To date, the biologic implications of cell fusion remain unclear. A newly developed in vivo tracking system was used to identify MSC fusion products in living mice. The migratory patterns of fusion products were determined both in the target organ (i

Induced pluripotent stem cell-derived gamete-associated proteins incite rejection of induced pluripotent stem cells in syngeneic mice.

PubMed

Kim, Eun-Mi; Manzar, Gohar; Zavazava, Nicholas

2017-06-01

The safety of induced pluripotent stem cells (iPSCs) in autologous recipients has been questioned after iPSCs, but not embryonic stem cells (ESCs), were reported to be rejected in syngeneic mice. This important topic has remained controversial because there has not been a mechanistic explanation for this phenomenon. Here, we hypothesize that iPSCs, but not ESCs, readily differentiate into gamete-forming cells that express meiotic antigens normally found in immune-privileged gonads. Because peripheral blood T cells are not tolerized to these antigens in the thymus, gamete-associated-proteins (GAPs) sensitize T cells leading to rejection. Here, we provide evidence that GAPs expressed in iPSC teratomas, but not in ESC teratomas, are responsible for the immunological rejection of iPSCs. Furthermore, silencing the expression of Stra8, 'the master regulator of meiosis', in iPSCs, using short hairpin RNA led to significant abrogation of the rejection of iPSCs, supporting our central hypothesis that GAPs expressed after initiation of meiosis in iPSCs were responsible for rejection. In contrast to iPSCs, iPSC-derivatives, such as haematopoietic progenitor cells, are able to engraft long-term into syngeneic recipients because they no longer express GAPs. Our findings, for the first time, provide a unifying explanation of why iPSCs, but not ESCs, are rejected in syngeneic recipients, ending the current controversy on the safety of iPSCs and their derivatives. © 2017 John Wiley & Sons Ltd.

Osteoclasts and giant cells: macrophage–macrophage fusion mechanism

PubMed Central

Vignery, Agnès

2000-01-01

) C domains. Shortly after we cloned MFR, CD47 was reported to be a ligand for P84/SIRPα. We have since generated preliminary results which suggest that CD47 interacts with MFR during adhesion/fusion and is a member of the fusion machinery. We also identified CD44 as a plasma membrane protein which, like MFR, is highly expressed at the onset of fusion. The recombinant soluble extracellular domain of CD44 blocks fusion by interacting with a cell-surface binding site. We now propose a model in which both forms of MFR, CD44, and CD47 mediate macrophage adhesion/fusion and therefore the differentiation of osteoclasts and giant cells. PMID:11168677

Fusion proteins of HIV-1 envelope glycoprotein gp120 with CD4-induced antibodies showed enhanced binding to CD4 and CD4 binding site antibodies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Weizao, E-mail: chenw3@mail.nih.gov; Feng, Yang; Wang, Yanping

Highlights: Black-Right-Pointing-Pointer Some recombinant HIV-1 gp120s do not preserve their conformations on gp140s. Black-Right-Pointing-Pointer We hypothesize that CD4i antibodies could induce conformational changes in gp120. Black-Right-Pointing-Pointer CD4i antibodies enhance binding of CD4 and CD4bs antibodies to gp120. Black-Right-Pointing-Pointer CD4i antibody-gp120 fusion proteins could have potential as vaccine immunogens. -- Abstract: Development of successful AIDS vaccine immunogens continues to be a major challenge. One of the mechanisms by which HIV-1 evades antibody-mediated neutralizing responses is the remarkable conformational flexibility of its envelope glycoprotein (Env) gp120. Some recombinant gp120s do not preserve their conformations on gp140s and functional viral spikes, and exhibitmore » decreased recognition by CD4 and neutralizing antibodies. CD4 binding induces conformational changes in gp120 leading to exposure of the coreceptor-binding site (CoRbs). In this study, we test our hypothesis that CD4-induced (CD4i) antibodies, which target the CoRbs, could also induce conformational changes in gp120 leading to better exposed conserved neutralizing antibody epitopes including the CD4-binding site (CD4bs). We found that a mixture of CD4i antibodies with gp120 only weakly enhanced CD4 binding. However, such interactions in single-chain fusion proteins resulted in gp120 conformations which bound to CD4 and CD4bs antibodies better than the original or mutagenically stabilized gp120s. Moreover, the two molecules in the fusion proteins synergized with each other in neutralizing HIV-1. Therefore, fusion proteins of gp120 with CD4i antibodies could have potential as components of HIV-1 vaccines and inhibitors of HIV-1 entry, and could be used as reagents to explore the conformational flexibility of gp120 and mechanisms of entry and immune evasion.« less

Dynamic Assembly of Brambleberry Mediates Nuclear Envelope Fusion during Early Development

PubMed Central

Abrams, Elliott W.; Zhang, Hong; Marlow, Florence L.; Kapp, Lee; Lu, Sumei; Mullins, Mary C.

2012-01-01

Summary To accommodate the large cells following zygote formation, early blastomeres employ modified cell divisions. Karyomeres are one such modification, a mitotic intermediate wherein individual chromatin masses are surrounded by nuclear envelope, which then fuse to form a single mononucleus. We identified brambleberry, a maternal-effect zebrafish mutant that disrupts karyomere fusion resulting in formation of multiple micronuclei. brambleberry is a previously unannotated gene homologous to Kar5p, which participates in nuclear fusion in yeast. We demonstrate that Brambleberry is required for pronuclear fusion following fertilization in zebrafish. As karyomeres form, Brambleberry localizes to the nuclear envelope with prominent puncta evident near karyomere-karyomere interfaces corresponding to membrane fusion sites. Our studies identify the first factor acting in karyomere fusion and suggest that specialized proteins are necessary for proper nuclear division in large dividing blastomeres. PMID:22863006

State fusion entropy for continuous and site-specific analysis of landslide stability changing regularities

NASA Astrophysics Data System (ADS)

Liu, Yong; Qin, Zhimeng; Hu, Baodan; Feng, Shuai

2018-04-01

Stability analysis is of great significance to landslide hazard prevention, especially the dynamic stability. However, many existing stability analysis methods are difficult to analyse the continuous landslide stability and its changing regularities in a uniform criterion due to the unique landslide geological conditions. Based on the relationship between displacement monitoring data, deformation states and landslide stability, a state fusion entropy method is herein proposed to derive landslide instability through a comprehensive multi-attribute entropy analysis of deformation states, which are defined by a proposed joint clustering method combining K-means and a cloud model. Taking Xintan landslide as the detailed case study, cumulative state fusion entropy presents an obvious increasing trend after the landslide entered accelerative deformation stage and historical maxima match highly with landslide macroscopic deformation behaviours in key time nodes. Reasonable results are also obtained in its application to several other landslides in the Three Gorges Reservoir in China. Combined with field survey, state fusion entropy may serve for assessing landslide stability and judging landslide evolutionary stages.

Gamete ripening and hormonal correlates in three strains of lake trout

USGS Publications Warehouse

Foster, N.R.; O'Connor, D.V.; Schreck, C.B.

1993-01-01

In our 2-year laboratory study of hatchery-reared adult lake trout Salvelinus namaycush of the Seneca Lake, Marquette (Lake Superior Lean), and Jenny Lake strains, we compared gamete ripening times and changes in plasma concentrations of seven hormones. If interstrain differences in these traits were found, such differences might help explain the apparent failure of stocked fish of these strains to develop large, naturally reproducing populations in the Great Lakes. The complex temporal changes in plasma hormone levels that occur during sexual maturation in lake trout have not been previously described. We detected little evidence of temporal isolation that would prevent interbreeding among the three strains. Strain had no effect on ovulation date (OD) in either year. Strain did not affect spermiation onset date (SOD) in year 1 but did in year 2, when the mean SOD of Jenny Lake males was earlier than that of Seneca Lake males but not different from that of Marquette males. Hormonal data were normalized around ODs for individual females and SODs for individual males. In females, estradiol-17β (E2) was highest 8 weeks before the OD; the highest testosterone (T) level occurred 6 weeks before the OD, and the next highest level occurred simultaneously with the highest level of 11-ketotestosterone (11-KT) 2 weeks before the OD. Plasma levels of 17∝-hydroxy-20β-dihydroprogesterone (DHP) peaked 1 week before the OD, then abruptly declined immediately after. Cortisol (F), triiodothyronine (T3), and thyroxine (T4) were highly variable, but F was the only hormone that showed no trend with week in either year. In males, plasma E2 levels were highest 3 weeks before the SOD, highest levels of T and of 11-KT occurred simultaneously 2 weeks after the SOD, and DHP peaked 5 weeks after the SOD and 3 weeks after the highest levels of T and 11-KT. As in females, plasma levels of F, T3, and T4 were highly variable, and F was the only hormone that showed no trend with week in

Iliac Crest Bone Graft versus Local Autograft or Allograft for Lumbar Spinal Fusion: A Systematic Review

PubMed Central

Tuchman, Alexander; Brodke, Darrel S.; Youssef, Jim A.; Meisel, Hans-Jörg; Dettori, Joseph R.; Park, Jong-Beom; Yoon, S. Tim; Wang, Jeffrey C.

2016-01-01

Study Design  Systematic review. Objective  To compare the effectiveness and safety between iliac crest bone graft (ICBG) and local autologous bone and allograft in the lumbar spine. Methods  A systematic search of multiple major medical reference databases identified studies evaluating spinal fusion in patients with degenerative joint disease using ICBG, local autograft, or allograft in the thoracolumbar spine. Results  Six comparative studies met our inclusion criteria. A “low” strength of the overall body of evidence suggested no difference in fusion percentages in the lumbar spine between local autograft and ICBG. We found no difference in fusion percentages based on low evidence comparing allograft with ICBG autograft. There were no differences in pain or functional results comparing local autograft or allograft with ICBG autograft. Donor site pain and hematoma/seroma occurred more frequently in ICBG autograft group for lumbar fusion procedures. There was low evidence around the estimate of patients with donor site pain following ICBG harvesting, ranging from 16.7 to 20%. With respect to revision, low evidence demonstrated no difference between allograft and ICBG autograft. There was no evidence comparing patients receiving allograft with local autograft for fusion, pain, functional, and safety outcomes. Conclusion  In the lumbar spine, ICBG, local autograft, and allograft have similar effectiveness in terms of fusion rates, pain scores, and functional outcomes. However, ICBG is associated with an increased risk for donor site-related complications. Significant limitations exist in the available literature when comparing ICBG, local autograft, and allograft for lumbar fusion, and thus ICBG versus other fusion methods necessitates further investigation. PMID:27556001

A quantitative assay for mitochondrial fusion using Renilla luciferase complementation

PubMed Central

Huang, Huiyan; Choi, Seok-Yong; Frohman, Michael A.

2010-01-01

Mitochondria continuously undergo fusion and fission, the relative rates of which define their morphology. Large mitochondria produce energy more efficiently, whereas small mitochondria translocate better to subcellular sites where local production of ATP is acutely required. Mitochondrial fusion is currently assayed by fusing together cells expressing GFP or RFP in their mitochondria and then scoring the frequency of cells with yellow mitochondria (representing fused green and red mitochondria). However, this assay is labor-intensive and only semi-quantitative. We describe here a reporter system consisting of split fragments of Renilla luciferase and YFP fused to mitochondrial matrix-targeting sequences and to leucine zippers to trigger dimerization. The assay enables fusion to be quantitated both visually for individual cells and on a population level using chemiluminescence, laying the foundation for high throughput small molecule and RNAi screens for modulators of mitochondrial fusion. We use the assay to examine cytoskeletal roles in fusion progression. PMID:20488258

A quantitative assay for mitochondrial fusion using Renilla luciferase complementation.

PubMed

Huang, Huiyan; Choi, Seok-Yong; Frohman, Michael A

2010-08-01

Mitochondria continuously undergo fusion and fission, the relative rates of which define their morphology. Large mitochondria produce energy more efficiently, whereas small mitochondria translocate better to subcellular sites where local production of ATP is acutely required. Mitochondrial fusion is currently assayed by fusing together cells expressing GFP or RFP in their mitochondria and then scoring the frequency of cells with yellow mitochondria (representing fused green and red mitochondria). However, this assay is labor-intensive and only semi-quantitative. We describe here a reporter system consisting of split fragments of Renilla luciferase and YFP fused to mitochondrial matrix-targeting sequences and to leucine zippers to trigger dimerization. The assay enables fusion to be quantitated both visually for individual cells and on a population level using chemiluminescence, laying the foundation for high throughput small molecule and RNAi screens for modulators of mitochondrial fusion. We use the assay to examine cytoskeletal roles in fusion progression. (c) 2010 Mitochondria Research Society. Published by Elsevier B.V. All rights reserved.

EDITORIAL: The Nuclear Fusion Award The Nuclear Fusion Award

NASA Astrophysics Data System (ADS)

Kikuchi, M.

2011-01-01

The Nuclear Fusion Award ceremony for 2009 and 2010 award winners was held during the 23rd IAEA Fusion Energy Conference in Daejeon. This time, both 2009 and 2010 award winners were celebrated by the IAEA and the participants of the 23rd IAEA Fusion Energy Conference. The Nuclear Fusion Award is a paper prize to acknowledge the best distinguished paper among the published papers in a particular volume of the Nuclear Fusion journal. Among the top-cited and highly-recommended papers chosen by the Editorial Board, excluding overview and review papers, and by analyzing self-citation and non-self-citation with an emphasis on non-self-citation, the Editorial Board confidentially selects ten distinguished papers as nominees for the Nuclear Fusion Award. Certificates are given to the leading authors of the Nuclear Fusion Award nominees. The final winner is selected among the ten nominees by the Nuclear Fusion Editorial Board voting confidentially. 2009 Nuclear Fusion Award nominees For the 2009 award, the papers published in the 2006 volume were assessed and the following papers were nominated, most of which are magnetic confinement experiments, theory and modeling, while one addresses inertial confinement. Sabbagh S.A. et al 2006 Resistive wall stabilized operation in rotating high beta NSTX plasmas Nucl. Fusion 46 635-44 La Haye R.J. et al 2006 Cross-machine benchmarking for ITER of neoclassical tearing mode stabilization by electron cyclotron current drive Nucl. Fusion 46 451-61 Honrubia J.J. et al 2006 Three-dimensional fast electron transport for ignition-scale inertial fusion capsules Nucl. Fusion 46 L25-8 Ido T. et al 2006 Observation of the interaction between the geodesic acoustic mode and ambient fluctuation in the JFT-2M tokamak Nucl. Fusion 46 512-20 Plyusnin V.V. et al 2006 Study of runaway electron generation during major disruptions in JET Nucl. Fusion 46 277-84 Pitts R.A. et al 2006 Far SOL ELM ion energies in JET Nucl. Fusion 46 82-98 Berk H.L. et al 2006

Fusion

NASA Astrophysics Data System (ADS)

Herman, Robin

1990-10-01

The book abounds with fascinating anecdotes about fusion's rocky path: the spurious claim by Argentine dictator Juan Peron in 1951 that his country had built a working fusion reactor, the rush by the United States to drop secrecy and publicize its fusion work as a propaganda offensive after the Russian success with Sputnik; the fortune Penthouse magazine publisher Bob Guccione sank into an unconventional fusion device, the skepticism that met an assertion by two University of Utah chemists in 1989 that they had created "cold fusion" in a bottle. Aimed at a general audience, the book describes the scientific basis of controlled fusion--the fusing of atomic nuclei, under conditions hotter than the sun, to release energy. Using personal recollections of scientists involved, it traces the history of this little-known international race that began during the Cold War in secret laboratories in the United States, Great Britain and the Soviet Union, and evolved into an astonishingly open collaboration between East and West.

Signal transduction at fertilization: the Ca2+ release pathway in echinoderms and other invertebrate deuterostomes.

PubMed

Townley, Ian K; Roux, Michelle M; Foltz, Kathy R

2006-04-01

Gamete interaction and fusion triggers a number of events that lead to egg activation and development of a new organism. A key event at fertilization is the rise in intracellular calcium. In deuterostomes, this calcium is released from the egg's endoplasmic reticulum and is necessary for proper activation. This article reviews recent data regarding how gamete interaction triggers the initial calcium release, focusing on the echinoderms (invertebrate deuterostomes) as model systems. In eggs of these animals, Src-type kinases and phospholipase C-gamma are required components of the initial calcium trigger pathway in eggs.

The cost-effectiveness of interbody fusions versus posterolateral fusions in 137 patients with lumbar spondylolisthesis.

PubMed

Bydon, Mohamad; Macki, Mohamed; Abt, Nicholas B; Witham, Timothy F; Wolinsky, Jean-Paul; Gokaslan, Ziya L; Bydon, Ali; Sciubba, Daniel M

2015-03-01

Reimbursements for interbody fusions have declined recently because of their questionable cost-effectiveness. A Markov model was adopted to compare the cost-effectiveness of posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (/TLIF) versus noninterbody fusion and posterolateral fusion (PLF) in patients with lumbar spondylolisthesis. Decision model analysis based on retrospective data from a single institutional series. One hundred thirty-seven patients underwent first-time instrumented lumbar fusions for degenerative or isthmic spondylolisthesis. Quality of life adjustments and expenditures were assigned to each short-term complication (durotomy, surgical site infection, and medical complication) and long-term outcome (bowel/bladder dysfunction and paraplegia, neurologic deficit, and chronic back pain). Patients were divided into a PLF cohort and a PLF plus PLIF/TLIF cohort. Anterior techniques and multilevel interbody fusions were excluded. Each short-term complication and long-term outcome was assigned a numerical quality-adjusted life-year (QALY), based on time trade-off values in the Beaver Dam Health Outcomes Study. The cost data for short-term complications were calculated from charges accrued by the institution's finance sector, and the cost data for long-term outcomes were estimated from the literature. The difference in cost of PLF plus PLIF/TLIF from the cost of PLF alone divided by the difference in QALY equals the cost-effectiveness ratio (CER). We do not report any study funding sources or any study-specific appraisal of potential conflict of interest-associated biases in this article. Of 137 first-time lumbar fusions for spondylolisthesis, 83 patients underwent PLF and 54 underwent PLIF/TLIF. The average time to reoperation was 3.5 years. The mean QALY over 3.5 years was 2.81 in the PLF cohort versus 2.66 in the PLIFo/TLIF cohort (p=.110). The mean 3.5-year costs of $54,827.05 after index interbody fusion were

Phosphatidylinositol 4,5-bisphosphate regulates SNARE-dependent membrane fusion.

PubMed

James, Declan J; Khodthong, Chuenchanok; Kowalchyk, Judith A; Martin, Thomas F J

2008-07-28

Phosphatidylinositol 4,5-bisphosphate (PI 4,5-P(2)) on the plasma membrane is essential for vesicle exocytosis but its role in membrane fusion has not been determined. Here, we quantify the concentration of PI 4,5-P(2) as approximately 6 mol% in the cytoplasmic leaflet of plasma membrane microdomains at sites of docked vesicles. At this concentration of PI 4,5-P(2) soluble NSF attachment protein receptor (SNARE)-dependent liposome fusion is inhibited. Inhibition by PI 4,5-P(2) likely results from its intrinsic positive curvature-promoting properties that inhibit formation of high negative curvature membrane fusion intermediates. Mutation of juxtamembrane basic residues in the plasma membrane SNARE syntaxin-1 increase inhibition by PI 4,5-P(2), suggesting that syntaxin sequesters PI 4,5-P(2) to alleviate inhibition. To define an essential rather than inhibitory role for PI 4,5-P(2), we test a PI 4,5-P(2)-binding priming factor required for vesicle exocytosis. Ca(2+)-dependent activator protein for secretion promotes increased rates of SNARE-dependent fusion that are PI 4,5-P(2) dependent. These results indicate that PI 4,5-P(2) regulates fusion both as a fusion restraint that syntaxin-1 alleviates and as an essential cofactor that recruits protein priming factors to facilitate SNARE-dependent fusion.

Dynamic assembly of brambleberry mediates nuclear envelope fusion during early development.

PubMed

Abrams, Elliott W; Zhang, Hong; Marlow, Florence L; Kapp, Lee; Lu, Sumei; Mullins, Mary C

2012-08-03

To accommodate the large cells following zygote formation, early blastomeres employ modified cell divisions. Karyomeres are one such modification, mitotic intermediates wherein individual chromatin masses are surrounded by nuclear envelope; the karyomeres then fuse to form a single mononucleus. We identified brambleberry, a maternal-effect zebrafish mutant that disrupts karyomere fusion, resulting in formation of multiple micronuclei. As karyomeres form, Brambleberry protein localizes to the nuclear envelope, with prominent puncta evident near karyomere-karyomere interfaces corresponding to membrane fusion sites. brambleberry corresponds to an unannotated gene with similarity to Kar5p, a protein that participates in nuclear fusion in yeast. We also demonstrate that Brambleberry is required for pronuclear fusion following fertilization in zebrafish. Our studies provide insight into the machinery required for karyomere fusion and suggest that specialized proteins are necessary for proper nuclear division in large dividing blastomeres. Copyright © 2012 Elsevier Inc. All rights reserved.

Lateral Membrane Heterogeneity Regulates Viral-Induced Membrane Fusion during HIV Entry

PubMed Central

Molotkovsky, Rodion J.; Alexandrova, Veronika V.; Galimzyanov, Timur R.; Jiménez-Munguía, Irene; Pavlov, Konstantin V.; Akimov, Sergey A.

2018-01-01

Sphingomyelin- and cholesterol- enriched membrane domains, commonly referred to as “rafts” play a crucial role in a large number of intra- and intercellular processes. Recent experiments suggest that not only the volumetric inhomogeneity of lipid distribution in rafts, but also the arrangement of the 1D boundary between the raft and the surrounding membrane is important for the membrane-associated processes. The reason is that the boundary preferentially recruits different peptides, such as HIV (human immunodeficiency virus) fusion peptide. In the present work, we report a theoretical investigation of mechanisms of influence of the raft boundary arrangement upon virus-induced membrane fusion. We theoretically predict that the raft boundary can act as an attractor for viral fusion peptides, which preferentially distribute into the vicinity of the boundary, playing the role of ‘line active components’ of the membrane (‘linactants’). We have calculated the height of the fusion energy barrier and demonstrated that, in the case of fusion between HIV membrane and the target cell, presence of the raft boundary in the vicinity of the fusion site facilitates fusion. The results we obtained can be further generalized to be applicable to other enveloped viruses. PMID:29772704

Lateral Membrane Heterogeneity Regulates Viral-Induced Membrane Fusion during HIV Entry.

PubMed

Molotkovsky, Rodion J; Alexandrova, Veronika V; Galimzyanov, Timur R; Jiménez-Munguía, Irene; Pavlov, Konstantin V; Batishchev, Oleg V; Akimov, Sergey A

2018-05-16

Sphingomyelin- and cholesterol- enriched membrane domains, commonly referred to as "rafts" play a crucial role in a large number of intra- and intercellular processes. Recent experiments suggest that not only the volumetric inhomogeneity of lipid distribution in rafts, but also the arrangement of the 1D boundary between the raft and the surrounding membrane is important for the membrane-associated processes. The reason is that the boundary preferentially recruits different peptides, such as HIV (human immunodeficiency virus) fusion peptide. In the present work, we report a theoretical investigation of mechanisms of influence of the raft boundary arrangement upon virus-induced membrane fusion. We theoretically predict that the raft boundary can act as an attractor for viral fusion peptides, which preferentially distribute into the vicinity of the boundary, playing the role of 'line active components' of the membrane ('linactants'). We have calculated the height of the fusion energy barrier and demonstrated that, in the case of fusion between HIV membrane and the target cell, presence of the raft boundary in the vicinity of the fusion site facilitates fusion. The results we obtained can be further generalized to be applicable to other enveloped viruses.

Intraoperative mechanical bone strength determination in tibiotalocalcaneal fusion: a biomechanical investigation.

PubMed

Klos, Kajetan; Windolf, Markus; Schwieger, Karsten; Kuhn, Philipp; Hänni, Markus; Gueorguiev, Boyko; Hofmann, Gunther O; Mückley, Thomas

2009-12-01

Bone strength is currently measured with indirect techniques. We investigated the use of an intraoperative mechanical measurement for local bone strength determination and prediction of intramedullary-nail fusion failure. We investigated whether intraoperative local bone strength determination may be useful to the surgeon in predicting intramedullary nail hindfoot fusion performance. In seven human specimens, bone mineral density (BMD) was determined with qCT. A device (DensiProbe) specially devised for nailed tibiotalocalcaneal arthrodesis (TTCA) was inserted at the intended calcaneal screw sites of an intramedullary nail, and the cancellous break-away torque was measured. The constructs were then cyclically loaded to failure in dorsiflexion-plantarfexion. The BMD range was wide (42.8 to 185.9 mg HA/cm(3)). The proximal-screw site peak torque was 0.47 to 1.61 Nm; distal-screw site peak torque was 0.24 to 1.06 Nm. The number of cycles to failure correlated with peak torque both proximally (p = 0.021; r(2) = 0.69) and distally (p = 0.001; r(2) = 0.92). Proximally, peak torque did not correlate with BMD (p = 0.060; r(2) = 0.54); distally, it correlated significantly (p = 0.003; r(2) = 0.86). DensiProbe measurements can be used in the hindfoot to assess bone strength. In this study, specimens that failed early could be identified. However, in clinical practice fusion failure is multifactorial in origin, and failure prediction cannot be based upon peak torque measurements alone. The technique described here may be of use to give an intraoperative decision aid to predict intramedullary nail hindfoot fusion performance.

Gamete rescue in the African black rhinoceros (Diceros bicornis).

PubMed

Stoops, M A; O'Brien, J K; Roth, T L

2011-10-15

Mortality rates are high among captive African black rhinoceroses (Diceros bicornis), due to increased susceptibility to disease. The ability to rescue genetic material from individuals that die unexpectedly represents a practical approach to assist ex situ conservation efforts. The objectives of the present study were to attempt postmortem oocyte recovery from ovaries of African black rhinoceroses (N = 6) and to test the efficacy of equine protocols for rhinoceros oocyte IVM and IVF using cryopreserved rhinoceros sperm. The interval from ovary removal to oocyte recovery was 25.3 ± 13.9 h (mean ± SD). Ovaries were transported at 4 °C or 22 °C and effects of temperature on postmortem oocyte competence was evaluated. Numbers of oocytes collected per female averaged 15.8 ± 6.9. In total, 95 oocytes were recovered. Of these, 85 were inseminated using homologous sperm and 10 were inseminated using heterologous sperm. Overall, substantial numbers of viable oocytes were retrieved from African black rhinoceros ovaries 1 to 2 days postmortem from ovaries stored at ambient temperature. A proportion of these oocytes matured and underwent penetration and fertilization by heterologous or homologous frozen-thawed rhinoceros sperm. The reproductive competence of postmortem oocytes was further demonstrated by development of a single two-cell embryo. Despite the need for further refinements, gamete rescue in the rhinoceros has promise for producing rhinoceros embryos, as well as testing sperm functions in vitro. Copyright © 2011 Elsevier Inc. All rights reserved.

Fusion peptide of influenza hemagglutinin requires a fixed angle boomerang structure for activity.

PubMed

Lai, Alex L; Park, Heather; White, Judith M; Tamm, Lukas K

2006-03-03

The fusion peptide of influenza hemagglutinin is crucial for cell entry of this virus. Previous studies showed that this peptide adopts a boomerang-shaped structure in lipid model membranes at the pH of membrane fusion. To examine the role of the boomerang in fusion, we changed several residues proposed to stabilize the kink in this structure and measured fusion. Among these, mutants E11A and W14A expressed hemagglutinins with hemifusion and no fusion activities, and F9A and N12A had no effect on fusion, respectively. Binding enthalpies and free energies of mutant peptides to model membranes and their ability to perturb lipid bilayer structures correlated well with the fusion activities of the parent full-length molecules. The structure of W14A determined by NMR and site-directed spin labeling features a flexible kink that points out of the membrane, in sharp contrast to the more ordered boomerang of the wild-type, which points into the membrane. A specific fixed angle boomerang structure is thus required to support membrane fusion.

Effect of gametes aging on their activation and fertilizability in zebrafish (Danio rerio).

PubMed

Cardona-Costa, Jose; Pérez-Camps, Mireia; García-Ximénez, Fernando; Espinós, Francisco J

2009-03-01

The zebrafish represents an important model organism for biological research. In this context, in vitro collection and fertilization of zebrafish gametes are basic and widely used techniques for many topical research works. In this work, the fertilization ability and normal embryo development of gold-type zebrafish sperm and eggs were re-evaluated after being stored for different times at 8 degrees C in a modified medium (Hanks' saline supplemented with 1.5 g BSA and 0.1 g ClNa; 320 mOsm, pH 7.4). Results obtained indicated that the temporal limits usually recommended for zebrafish sperm to fertilize fresh eggs (2 h) could be extended for up to 24 h without significant differences compared with fresh sperm. In contrast, the rapid egg aging observed (even less than 1 h) recommends minimizing as far as possible the egg storage time before fertilization. These results suggest a possible strain difference in the fertilization response.

Early experience with gamete intrafallopian transfer (GIFT) and direct intraperitoneal insemination (DIPI).

PubMed Central

Dooley, M; Lim-Howe, D; Savvas, M; Studd, J W

1988-01-01

We present our early experience with gamete intrafallopian transfer (GIFT) and direct intraperitoneal insemination (DIPI) combined with intrauterine insemination (IUI), two recently described methods of assisting conception in patients with patent fallopian tubes. Sixty-nine patients (93 cycles) were entered into the study. Thirty-three patients (51 cycles) entered the DIPI/IUI programme and 36 patients (42 cycles) entered the GIFT programme. The mean age, duration and aetiology of infertility were similar in both groups. In the GIFT programme 12 pregnancies occurred, which is a 29% pregnancy rate per cycle and a 33% pregnancy rate per patient. In the DIPI/IUI programme only 3 pregnancies occurred, being a 6% pregnancy rate per cycle and a 9% pregnancy rate per patient. With the live birth rate of in vitro fertilization (IVF) being 12% per embryo transfer, we conclude that GIFT is more successful than either DIPI/IUI or IVF in patients with patent fallopian tubes. Further controlled studies are required to assess the future role of DIPI/IUI in clinical practice. PMID:3210194

Expression and localization of tubulin cofactors TBCD and TBCE in human gametes.

PubMed

Jiménez-Moreno, Victoria; Agirregoitia, Ekaitz

2017-06-01

The tubulin cofactors TBCD and TBCE play an essential role in regulation of the microtubule dynamics in a wide variety of somatic cells, but little information is known about the expression of these cofactors in human sperm and oocytes. In this study, we focused on the investigation of the presence of, and the differential distribution of, the tubulin cofactors TBCD and TBCE in human sperm and during human oocyte maturation. We performed expression assays for TBCD and TBCE by reverse transcription-polymerase chain reaction (RT-PCR), western blot and immunofluorescence and verified the presence of both cofactors in human gametes. TBCD and TBCE were located mainly in the middle region and in the tail of the sperm while in the oocyte the localization was cytosolic. The mRNA of both tubulin cofactors were present in the human oocytes but not in sperm cells. This finding gives a first insight into where TBCD and TBCE could carry out their function in the continuous changes that the cytoskeleton experiences during gametogenesis and also prior to fertilization.

Investigation of fusion gene expression in HCT116 cells.

PubMed

Zhang, Yanmei; Ren, Juan; Fang, Mengdie; Wang, Xiaoju

2017-12-01

Colon cancer is the most common type of gastrointestinal cancer. A number of specific and sensitive biomarkers facilitate the diagnosis and monitoring of patients with colon cancer. Fusion genes are typically identified in cancer and a majority of the newly identified fusion genes are oncogenic in nature. Therefore, fusion genes are potential biomarkers and/or therapy targets in cancer. In the present study, the regulation of specific candidate fusion genes were investigated using Brother of the Regulator of Imprinted Sites (BORIS) in the HCT116 colon cancer cell line, which is a paralog of the fusion gene regulator CCCTC-binding factor (CTCF). The copy number of BORIS increased correspondingly to the progression of colorectal carcinoma from the M0 to the M1a stage. It was identified that EIF3E(e1)-RSPO2(e2) , EIF3E(e1)-RSPO2(e3) , PTPRK(e1)-RSPO3(e2) , PTPRK(e7)-RSPO3(e2), TADA2A-MEF2B and MED13L-CD4 are fusion transcripts present in the transcriptome of the HCT116 colon cancer cell line. CDC42SE2-KIAAO146 is a genomic fusion transcript, which originates from DNA arrangement in HCT116 cells. BORIS suppresses the expression of EIF3E , RSPO2 , PTPRK , RSPO3 , TADA2A and CD4 to inhibit the expression of fusion transcripts in HCT116 cells. It was hypothesized that the fusion transcripts investigated in the present study may not be oncogenic in HCT116 cells. As BORIS is not colorectal carcinoma-specific, the fusion genes investigated may be a biomarker assemblage for monitoring the progression of colorectal carcinoma.

Investigation of fusion gene expression in HCT116 cells

PubMed Central

Zhang, Yanmei; Ren, Juan; Fang, Mengdie; Wang, Xiaoju

2017-01-01

Colon cancer is the most common type of gastrointestinal cancer. A number of specific and sensitive biomarkers facilitate the diagnosis and monitoring of patients with colon cancer. Fusion genes are typically identified in cancer and a majority of the newly identified fusion genes are oncogenic in nature. Therefore, fusion genes are potential biomarkers and/or therapy targets in cancer. In the present study, the regulation of specific candidate fusion genes were investigated using Brother of the Regulator of Imprinted Sites (BORIS) in the HCT116 colon cancer cell line, which is a paralog of the fusion gene regulator CCCTC-binding factor (CTCF). The copy number of BORIS increased correspondingly to the progression of colorectal carcinoma from the M0 to the M1a stage. It was identified that EIF3E(e1)-RSPO2(e2), EIF3E(e1)-RSPO2(e3), PTPRK(e1)-RSPO3(e2), PTPRK(e7)-RSPO3(e2), TADA2A-MEF2B and MED13L-CD4 are fusion transcripts present in the transcriptome of the HCT116 colon cancer cell line. CDC42SE2-KIAAO146 is a genomic fusion transcript, which originates from DNA arrangement in HCT116 cells. BORIS suppresses the expression of EIF3E, RSPO2, PTPRK, RSPO3, TADA2A and CD4 to inhibit the expression of fusion transcripts in HCT116 cells. It was hypothesized that the fusion transcripts investigated in the present study may not be oncogenic in HCT116 cells. As BORIS is not colorectal carcinoma-specific, the fusion genes investigated may be a biomarker assemblage for monitoring the progression of colorectal carcinoma. PMID:29181107

The impact of preoperative epidural injections on postoperative infection in lumbar fusion surgery.

PubMed

Singla, Anuj; Yang, Scott; Werner, Brian C; Cancienne, Jourdan M; Nourbakhsh, Ali; Shimer, Adam L; Hassanzadeh, Hamid; Shen, Francis H

2017-05-01

OBJECTIVE Lumbar epidural steroid injections (LESIs) are performed for both diagnostic and therapeutic purposes for a variety of indications, including low-back pain, the leading cause of disability and expense due to work-related conditions in the US. The steroid agent used in epidural injections is reported to relieve nerve root inflammation, local ischemia, and resultant pain, but the injection may also have an adverse impact on spinal surgery performed thereafter. In particular, the possibility that preoperative epidural injections may increase the risk of surgical site infection after lumbar spinal fusion has been reported but has not been studied in detail. The goal of the present study was to use a large national insurance database to analyze the association of preoperative LESIs with surgical site infection after lumbar spinal fusion. METHODS A nationwide insurance database of patient records was used for this retrospective analysis. Current Procedural Terminology codes were used to query the database for patients who had undergone LESI and 1- or 2-level lumbar posterior spinal fusion procedures. The rate of postoperative infection after 1- or 2-level posterior spinal fusion was analyzed. These study patients were then divided into 3 separate cohorts: 1) lumbar spinal fusion performed within 1 month after LESI, 2) fusion performed between 1 and 3 months after LESI, and 3) fusion performed between 3 and 6 months after LESI. The study patients were compared with a control cohort of patients who underwent lumbar fusion without previous LESI. RESULTS The overall 3-month infection rate after lumbar spinal fusion procedure was 1.6% (1411 of 88,540 patients). The infection risk increased in patients who received LESI within 1 month (OR 2.6, p < 0.0001) or 1-3 months (OR 1.4, p = 0.0002) prior to surgery compared with controls. The infection risk was not significantly different from controls in patients who underwent lumbar fusion more than 3 months after LESI

High Level Information Fusion (HLIF) with nested fusion loops

NASA Astrophysics Data System (ADS)

Woodley, Robert; Gosnell, Michael; Fischer, Amber

2013-05-01

Situation modeling and threat prediction require higher levels of data fusion in order to provide actionable information. Beyond the sensor data and sources the analyst has access to, the use of out-sourced and re-sourced data is becoming common. Through the years, some common frameworks have emerged for dealing with information fusion—perhaps the most ubiquitous being the JDL Data Fusion Group and their initial 4-level data fusion model. Since these initial developments, numerous models of information fusion have emerged, hoping to better capture the human-centric process of data analyses within a machine-centric framework. 21st Century Systems, Inc. has developed Fusion with Uncertainty Reasoning using Nested Assessment Characterizer Elements (FURNACE) to address challenges of high level information fusion and handle bias, ambiguity, and uncertainty (BAU) for Situation Modeling, Threat Modeling, and Threat Prediction. It combines JDL fusion levels with nested fusion loops and state-of-the-art data reasoning. Initial research has shown that FURNACE is able to reduce BAU and improve the fusion process by allowing high level information fusion (HLIF) to affect lower levels without the double counting of information or other biasing issues. The initial FURNACE project was focused on the underlying algorithms to produce a fusion system able to handle BAU and repurposed data in a cohesive manner. FURNACE supports analyst's efforts to develop situation models, threat models, and threat predictions to increase situational awareness of the battlespace. FURNACE will not only revolutionize the military intelligence realm, but also benefit the larger homeland defense, law enforcement, and business intelligence markets.

TALE-PvuII fusion proteins--novel tools for gene targeting.

PubMed

Yanik, Mert; Alzubi, Jamal; Lahaye, Thomas; Cathomen, Toni; Pingoud, Alfred; Wende, Wolfgang

2013-01-01

Zinc finger nucleases (ZFNs) consist of zinc fingers as DNA-binding module and the non-specific DNA-cleavage domain of the restriction endonuclease FokI as DNA-cleavage module. This architecture is also used by TALE nucleases (TALENs), in which the DNA-binding modules of the ZFNs have been replaced by DNA-binding domains based on transcription activator like effector (TALE) proteins. Both TALENs and ZFNs are programmable nucleases which rely on the dimerization of FokI to induce double-strand DNA cleavage at the target site after recognition of the target DNA by the respective DNA-binding module. TALENs seem to have an advantage over ZFNs, as the assembly of TALE proteins is easier than that of ZFNs. Here, we present evidence that variant TALENs can be produced by replacing the catalytic domain of FokI with the restriction endonuclease PvuII. These fusion proteins recognize only the composite recognition site consisting of the target site of the TALE protein and the PvuII recognition sequence (addressed site), but not isolated TALE or PvuII recognition sites (unaddressed sites), even at high excess of protein over DNA and long incubation times. In vitro, their preference for an addressed over an unaddressed site is > 34,000-fold. Moreover, TALE-PvuII fusion proteins are active in cellula with minimal cytotoxicity.

INTRODUCTION: Status report on fusion research

NASA Astrophysics Data System (ADS)

Burkart, Werner

2005-10-01

A major milestone on the path to fusion energy was reached in June 2005 on the occasion of the signing of the joint declaration of all parties to the ITER negotiations, agreeing on future arrangements and on the construction site at Cadarache in France. The International Atomic Energy Agency has been promoting fusion activities since the late 1950s; it took over the auspices of the ITER Conceptual Design Activities in 1988, and of the ITER Engineering and Design Activities in 1992. The Agency continues its support to Member States through the organization of consultancies, workshops and technical meetings, the most prominent being the series of International Fusion Energy Conferences (formerly called the International Conference on Plasma Physics and Controlled Nuclear Fusion Research). The meetings serve as a platform for experts from all Member States to have open discussions on their latest accomplishments as well as on their problems and eventual solutions. The papers presented at the meetings and conferences are routinely published, many being sent to the journal it Nuclear Fusion, co-published monthly by Institute of Physics Publishing, Bristol, UK. The journal's reputation is reflected in the fact that it is a world-renowned publication, and the International Fusion Research Council has used it for the publication of a Status Report on Controlled Thermonuclear Fusion in 1978 and 1990. This present report marks the conclusion of the preparatory phases of ITER activities. It provides background information on the progress of fusion research within the last 15 years. The International Fusion Research Council (IFRC), which initiated the report, was fully aware of the complexities of including all scientific results in just one paper, and so decided to provide an overview and extensive references for the interested reader who need not necessarily be a fusion specialist. Professor Predhiman K. Kaw, Chairman, prepared the report on behalf of the IFRC, reflecting

Mating-Induced Shedding of Cell Walls, Removal of Walls from Vegetative Cells, and Osmotic Stress Induce Presumed Cell Wall Genes in Chlamydomonas1

PubMed Central

Hoffmann, Xenia-Katharina; Beck, Christoph F.

2005-01-01

The first step in sexual differentiation of the unicellular green alga Chlamydomonas reinhardtii is the formation of gametes. Three genes, GAS28, GAS30, and GAS31, encoding Hyp-rich glycoproteins that presumably are cell wall constituents, are expressed in the late phase of gametogenesis. These genes, in addition, are activated by zygote formation and cell wall removal and by the application of osmotic stress. The induction by zygote formation could be traced to cell wall shedding prior to gamete fusion since it was seen in mutants defective in cell fusion. However, it was absent in mutants defective in the initial steps of mating, i.e. in flagellar agglutination and in accumulation of adenosine 3′,5′-cyclic monophosphate in response to this agglutination. Induction of the three GAS genes was also observed when cultures were exposed to hypoosmotic or hyperosmotic stress. To address the question whether the induction seen upon cell wall removal from both gametes and vegetative cells was elicited by osmotic stress, cell wall removal was performed under isosmotic conditions. Also under such conditions an activation of the genes was observed, suggesting that the signaling pathway(s) is (are) activated by wall removal itself. PMID:16183845

Confocal observations of late-acting self-incompatibility in Theobroma cacao L.

PubMed

Ford, Caroline S; Wilkinson, Mike J

2012-09-01

Cocoa (Theobroma cacao) has an idiosyncratic form of late-acting self-incompatibility that operates through the non-fusion of incompatible gametes. Here, we used high-resolution confocal microscopy to define fine level changes to the embryo sac of the strongly self-incompatible cocoa genotype SCA 24 in the absence of pollination, and following compatible and incompatible pollination. All sperm nuclei had fused with the female nuclei by 48 h following compatible pollinations. However, following incompatible pollinations, we observed divergence in the behaviour of sperm nuclei following release into the embryo sac. Incomplete sperm nucleus migration occurred in approximately half of the embryo sacs, where the sperm nuclei had so far failed to reach the female gamete nuclei. Sperm nuclei reached but did not fuse with the female gamete nuclei in the residual cases. We argue that the cellular mechanisms governing sperm nucleus migration to the egg nucleus and those controlling subsequent nuclear fusion are likely to differ and should be considered independently. Accordingly, we recommend that future efforts to characterise the genetic basis of LSI in cocoa should take care to differentiate between these two events, both of which contribute to failed karyogamy. Implications of these results for continuing efforts to gain better understanding of the genetic control of LSI in cocoa are discussed.

Fusion breeder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moir, R.W.

1982-02-22

The fusion breeder is a fusion reactor designed with special blankets to maximize the transmutation by 14 MeV neutrons of uranium-238 to plutonium or thorium to uranium-233 for use as a fuel for fission reactors. Breeding fissile fuels has not been a goal of the US fusion energy program. This paper suggests it is time for a policy change to make the fusion breeder a goal of the US fusion program and the US nuclear energy program. The purpose of this paper is to suggest this policy change be made and tell why it should be made, and to outlinemore » specific research and development goals so that the fusion breeder will be developed in time to meet fissile fuel needs.« less

Fusion breeder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moir, R.W.

1982-04-20

The fusion breeder is a fusion reactor designed with special blankets to maximize the transmutation by 14 MeV neutrons of uranium-238 to plutonium or thorium to uranium-233 for use as a fuel for fission reactors. Breeding fissile fuels has not been a goal of the US fusion energy program. This paper suggests it is time for a policy change to make the fusion breeder a goal of the US fusion program and the US nuclear energy program. The purpose of this paper is to suggest this policy change be made and tell why it should be made, and to outlinemore » specific research and development goals so that the fusion breeder will be developed in time to meet fissile fuel needs.« less

Viral membrane fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrison, Stephen C., E-mail: harrison@crystal.harvard.edu

2015-05-15

Membrane fusion is an essential step when enveloped viruses enter cells. Lipid bilayer fusion requires catalysis to overcome a high kinetic barrier; viral fusion proteins are the agents that fulfill this catalytic function. Despite a variety of molecular architectures, these proteins facilitate fusion by essentially the same generic mechanism. Stimulated by a signal associated with arrival at the cell to be infected (e.g., receptor or co-receptor binding, proton binding in an endosome), they undergo a series of conformational changes. A hydrophobic segment (a “fusion loop” or “fusion peptide”) engages the target-cell membrane and collapse of the bridging intermediate thus formedmore » draws the two membranes (virus and cell) together. We know of three structural classes for viral fusion proteins. Structures for both pre- and postfusion conformations of illustrate the beginning and end points of a process that can be probed by single-virion measurements of fusion kinetics. - Highlights: • Viral fusion proteins overcome the high energy barrier to lipid bilayer merger. • Different molecular structures but the same catalytic mechanism. • Review describes properties of three known fusion-protein structural classes. • Single-virion fusion experiments elucidate mechanism.« less

Paramyxovirus fusion: Real-time measurement of parainfluenza virus 5 virus-cell fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Connolly, Sarah A.; Lamb, Robert A.

2006-11-25

Although cell-cell fusion assays are useful surrogate methods for studying virus fusion, differences between cell-cell and virus-cell fusion exist. To examine paramyxovirus fusion in real time, we labeled viruses with fluorescent lipid probes and monitored virus-cell fusion by fluorimetry. Two parainfluenza virus 5 (PIV5) isolates (W3A and SER) and PIV5 containing mutations within the fusion protein (F) were studied. Fusion was specific and temperature-dependent. Compared to many low pH-dependent viruses, the kinetics of PIV5 fusion was slow, approaching completion within several minutes. As predicted from cell-cell fusion assays, virus containing an F protein with an extended cytoplasmic tail (rSV5 F551)more » had reduced fusion compared to wild-type virus (W3A). In contrast, virus-cell fusion for SER occurred at near wild-type levels, despite the fact that this isolate exhibits a severely reduced cell-cell fusion phenotype. These results support the notion that virus-cell and cell-cell fusion have significant differences.« less

The influence of sperm concentration, length of the gamete co-culture and the evolution of different sperm parameters on the in vitro fertilization of prepubertal goat oocytes.

PubMed

Palomo, M J; Mogas, T; Izquierdo, D; Paramio, M T

2010-11-01

The aims of the present study were: (1) to evaluate the influence of sperm concentration (ranging from 0.5 × 10(6) to 4 × 10(6) spermatozoa/ml) and length of the gamete co-incubation time (2, 4, 6, 8, 10, 12, 16, 20, 24 or 28 h) on in vitro fertilization (IVF), assessing the sperm penetration rate; (2) to investigate the kinetics of different semen parameters as motility, viability and acrosome status during the co-culture period; and (3) to analyse the effect of the presence of cumulus-oocytes complexes (COCs) on these parameters. To achieve these objectives, several experiments were carried out using in vitro matured oocytes from prepubertal goats. The main findings of this work are that: (1) in our conditions, the optimum sperm concentration is 4 × 10(6) sperm/ml, as this sperm:oocyte ratio (approximately 28,000) allowed us to obtain the highest penetration rate, without increasing polyspermy incidence; (2) the highest percentage of viable acrosome-reacted spermatozoa is observed between 8-12 h of gamete co-culture, while the penetration rate is maximum at 12 h of co-incubation; and (3) the presence of COCs seems to favour the acrosome reaction of free spermatozoa on IVF medium, but not significantly. In conclusion, we suggest that a gamete co-incubation for 12-14 h, with a concentration of 4 × 10(6) sperm/ml, would be sufficient to obtain the highest rate of penetration, reducing the exposure of oocytes to high levels of reactive oxygen species produced by spermatozoa, especially when a high sperm concentration is used to increase the caprine IVF outcome.

Polyploidization and cell fusion contribute to wound healing in the adult Drosophila epithelium

PubMed Central

Losick, Vicki P.; Fox, Donald T.; Spradling, Allan C.

2014-01-01

Summary Background Re-establishing epithelial integrity and biosynthetic capacity is critically important following tissue damage. The adult Drosophila abdominal epithelium provides an attractive new system to address how post-mitotic diploid cells contribute to repair. Results Puncture wounds to the adult Drosophila epidermis close initially by forming a melanized scab. We found that epithelial cells near the wound site fuse to form a giant syncytium, which sends lamellae under the scab to re-epithelialize the damaged site. Other large cells arise more peripherally by initiating endocycles and becoming polyploid, or by cell fusion. Rac GTPase activity is needed for syncytium formation, while the Hippo signaling effector Yorkie modulates both polyploidization and cell fusion. Large cell formation is functionally important because when both polyploidization and fusion are blocked, wounds do not re-epithelialize. Conclusions Our observations indicate that cell mass lost upon wounding can be replaced by polyploidization instead of mitotic proliferation. We propose that large cells generated by polyploidization or cell fusion are essential because they are better able than diploid cells to mechanically stabilize wounds, especially those containing permanent acellular structures, such as scar tissue. PMID:24184101

Polyploidization and cell fusion contribute to wound healing in the adult Drosophila epithelium.

PubMed

Losick, Vicki P; Fox, Donald T; Spradling, Allan C

2013-11-18

Reestablishing epithelial integrity and biosynthetic capacity is critically important following tissue damage. The adult Drosophila abdominal epithelium provides an attractive new system to address how postmitotic diploid cells contribute to repair. Puncture wounds to the adult Drosophila epidermis close initially by forming a melanized scab. We found that epithelial cells near the wound site fuse to form a giant syncytium, which sends lamellae under the scab to re-epithelialize the damaged site. Other large cells arise more peripherally by initiating endocycles and becoming polyploid, or by cell fusion. Rac GTPase activity is needed for syncytium formation, while the Hippo signaling effector Yorkie modulates both polyploidization and cell fusion. Large cell formation is functionally important because when both polyploidization and fusion are blocked, wounds do not re-epithelialize. Our observations indicate that cell mass lost upon wounding can be replaced by polyploidization instead of mitotic proliferation. We propose that large cells generated by polyploidization or cell fusion are essential because they are better able than diploid cells to mechanically stabilize wounds, especially those containing permanent acellular structures, such as scar tissue. Copyright © 2013 Elsevier Ltd. All rights reserved.

Entropic forces drive self-organization and membrane fusion by SNARE proteins

PubMed Central

Stratton, Benjamin S.; Warner, Jason M.; Rothman, James E.; O’Shaughnessy, Ben

2017-01-01

SNARE proteins are the core of the cell’s fusion machinery and mediate virtually all known intracellular membrane fusion reactions on which exocytosis and trafficking depend. Fusion is catalyzed when vesicle-associated v-SNAREs form trans-SNARE complexes (“SNAREpins”) with target membrane-associated t-SNAREs, a zippering-like process releasing ∼65 kT per SNAREpin. Fusion requires several SNAREpins, but how they cooperate is unknown and reports of the number required vary widely. To capture the collective behavior on the long timescales of fusion, we developed a highly coarse-grained model that retains key biophysical SNARE properties such as the zippering energy landscape and the surface charge distribution. In simulations the ∼65-kT zippering energy was almost entirely dissipated, with fully assembled SNARE motifs but uncomplexed linker domains. The SNAREpins self-organized into a circular cluster at the fusion site, driven by entropic forces that originate in steric–electrostatic interactions among SNAREpins and membranes. Cooperative entropic forces expanded the cluster and pulled the membranes together at the center point with high force. We find that there is no critical number of SNAREs required for fusion, but instead the fusion rate increases rapidly with the number of SNAREpins due to increasing entropic forces. We hypothesize that this principle finds physiological use to boost fusion rates to meet the demanding timescales of neurotransmission, exploiting the large number of v-SNAREs available in synaptic vesicles. Once in an unfettered cluster, we estimate ≥15 SNAREpins are required for fusion within the ∼1-ms timescale of neurotransmitter release. PMID:28490503

Sequence variability of the respiratory syncytial virus (RSV) fusion gene among contemporary and historical genotypes of RSV/A and RSV/B

PubMed Central

Hause, Anne M.; Henke, David M.; Avadhanula, Vasanthi; Shaw, Chad A.; Tapia, Lorena I.

2017-01-01

Background The fusion (F) protein of RSV is the major vaccine target. This protein undergoes a conformational change from pre-fusion to post-fusion. Both conformations share antigenic sites II and IV. Pre-fusion F has unique antigenic sites p27, ø, α2α3β3β4, and MPE8; whereas, post-fusion F has unique antigenic site I. Our objective was to determine the antigenic variability for RSV/A and RSV/B isolates from contemporary and historical genotypes compared to a historical RSV/A strain. Methods The F sequences of isolates from GenBank, Houston, and Chile (N = 1,090) were used for this analysis. Sequences were compared pair-wise to a reference sequence, a historical RSV/A Long strain. Variability (calculated as %) was defined as changes at each amino acid (aa) position when compared to the reference sequence. Only aa at antigenic sites with variability ≥5% were reported. Results A total of 1,090 sequences (822 RSV/A and 268 RSV/B) were analyzed. When compared to the reference F, those domains with the greatest number of non-synonymous changes included the signal peptide, p27, heptad repeat domain 2, antigenic site ø, and the transmembrane domain. RSV/A subgroup had 7 aa changes in the antigenic sites: site I (N = 1), II (N = 1), p27 (N = 4), α2α3β3β4(AM14) (N = 1), ranging in frequency from 7–91%. In comparison, RSV/B had 19 aa changes in antigenic sites: I (N = 3), II (N = 1), p27 (N = 9), ø (N = 4), α2α3β3β4(AM14) (N = 1), and MPE8 (N = 1), ranging in frequency from 79–100%. Discussion Although antigenic sites of RSV F are generally well conserved, differences are observed when comparing the two subgroups to the reference RSV/A Long strain. Further, these discrepancies are accented in the antigenic sites in pre-fusion F of RSV/B isolates, often occurring with a frequency of 100%. This could be of importance if a monovalent F protein from the historical GA1 genotype of RSV/A is used for vaccine development. PMID:28414749

Sequence variability of the respiratory syncytial virus (RSV) fusion gene among contemporary and historical genotypes of RSV/A and RSV/B.

PubMed

Hause, Anne M; Henke, David M; Avadhanula, Vasanthi; Shaw, Chad A; Tapia, Lorena I; Piedra, Pedro A

2017-01-01

The fusion (F) protein of RSV is the major vaccine target. This protein undergoes a conformational change from pre-fusion to post-fusion. Both conformations share antigenic sites II and IV. Pre-fusion F has unique antigenic sites p27, ø, α2α3β3β4, and MPE8; whereas, post-fusion F has unique antigenic site I. Our objective was to determine the antigenic variability for RSV/A and RSV/B isolates from contemporary and historical genotypes compared to a historical RSV/A strain. The F sequences of isolates from GenBank, Houston, and Chile (N = 1,090) were used for this analysis. Sequences were compared pair-wise to a reference sequence, a historical RSV/A Long strain. Variability (calculated as %) was defined as changes at each amino acid (aa) position when compared to the reference sequence. Only aa at antigenic sites with variability ≥5% were reported. A total of 1,090 sequences (822 RSV/A and 268 RSV/B) were analyzed. When compared to the reference F, those domains with the greatest number of non-synonymous changes included the signal peptide, p27, heptad repeat domain 2, antigenic site ø, and the transmembrane domain. RSV/A subgroup had 7 aa changes in the antigenic sites: site I (N = 1), II (N = 1), p27 (N = 4), α2α3β3β4(AM14) (N = 1), ranging in frequency from 7-91%. In comparison, RSV/B had 19 aa changes in antigenic sites: I (N = 3), II (N = 1), p27 (N = 9), ø (N = 4), α2α3β3β4(AM14) (N = 1), and MPE8 (N = 1), ranging in frequency from 79-100%. Although antigenic sites of RSV F are generally well conserved, differences are observed when comparing the two subgroups to the reference RSV/A Long strain. Further, these discrepancies are accented in the antigenic sites in pre-fusion F of RSV/B isolates, often occurring with a frequency of 100%. This could be of importance if a monovalent F protein from the historical GA1 genotype of RSV/A is used for vaccine development.

A tethering complex drives the terminal stage of SNARE-dependent membrane fusion

NASA Astrophysics Data System (ADS)

D'Agostino, Massimo; Risselada, Herre Jelger; Lürick, Anna; Ungermann, Christian; Mayer, Andreas

2017-11-01

Membrane fusion in eukaryotic cells mediates the biogenesis of organelles, vesicular traffic between them, and exo- and endocytosis of important signalling molecules, such as hormones and neurotransmitters. Distinct tasks in intracellular membrane fusion have been assigned to conserved protein systems. Tethering proteins mediate the initial recognition and attachment of membranes, whereas SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein complexes are considered as the core fusion engine. SNARE complexes provide mechanical energy to distort membranes and drive them through a hemifusion intermediate towards the formation of a fusion pore. This last step is highly energy-demanding. Here we combine the in vivo and in vitro fusion of yeast vacuoles with molecular simulations to show that tethering proteins are critical for overcoming the final energy barrier to fusion pore formation. SNAREs alone drive vacuoles only into the hemifused state. Tethering proteins greatly increase the volume of SNARE complexes and deform the site of hemifusion, which lowers the energy barrier for pore opening and provides the driving force. Thereby, tethering proteins assume a crucial mechanical role in the terminal stage of membrane fusion that is likely to be conserved at multiple steps of vesicular traffic. We therefore propose that SNAREs and tethering proteins should be considered as a single, non-dissociable device that drives fusion. The core fusion machinery may then be larger and more complex than previously thought.

Five Residues in the Apical Loop of the Respiratory Syncytial Virus Fusion Protein F2 Subunit are Critical for its Fusion Activity.

PubMed

Hicks, Stephanie N; Chaiwatpongsakorn, Supranee; Costello, Heather M; McLellan, Jason S; Ray, William; Peeples, Mark E

2018-05-09

The respiratory syncytial virus (RSV) fusion (F) protein is a trimeric, membrane-anchored glycoprotein capable of mediating both viral-target cell membrane fusion to initiate infection and cell-cell fusion, even in the absence of the attachment glycoprotein. The F protein is initially expressed in a precursor form, whose functional capabilities are activated by proteolysis at two sites between the F 1 and F 2 subunits. This cleavage results in expression of the metastable and high-energy prefusion conformation. To mediate fusion, the F protein is triggered by an unknown stimulus, causing the F 1 subunit to refold dramatically while F 2 changes minimally. Hypothesizing that the most likely site for interaction with a target-cell component would be the top, or apex, of the protein, we determined the importance of the residues in the apical loop of F 2 by scanning mutagenesis. Five residues were not important, two were of intermediate importance, and all four lysines and one isoleucine were essential. Alanine replacement did not result in the loss of pre-F conformation for any of these mutants. Each of the four lysines required its specific charge for fusion function. Alanine replacement of the three essential lysines on the ascent to the apex hindered fusion following a forced fusion event, suggesting they are involved in refolding. Alanine mutation at Ile64, also on the ascent to the apex, and Lys75, did not prevent fusion following forced triggering, suggesting they are not involved in refolding and may instead be involved in the natural triggering of the F protein. IMPORTANCE RSV infects virtually every child by the age of 3, causing nearly 33 million acute lower respiratory infections (ALRI) worldwide each year in children younger than 5 (Nair H, et al. 2010. Lancet 375:1545-55). RSV is also the second leading cause of respiratory related death in the elderly (Falsey AR, Walsh EE. 2005. Drugs Aging 22:577-87; Falsey AR, Hennessey PA, Formica MA, Cox C, Walsh EE

Preliminary Comparison of Radioactive Waste Disposal Cost for Fusion and Fission Reactors

NASA Astrophysics Data System (ADS)

Seki, Yasushi; Aoki, Isao; Yamano, Naoki; Tabara, Takashi

1997-09-01

The environmental and economic impact of radioactive waste (radwaste) generated from fusion power reactors using five types of structural materials and a fission reactor has been evaluated and compared. Possible radwaste disposal scenario of fusion radwaste in Japan is considered. The exposure doses were evaluated for the skyshine of gamma-ray during the disposal operation, groundwater migration scenario during the institutional control period of 300 years and future site use scenario after the institutional period. The radwaste generated from a typical light water fission reactor was evaluated using the same methodology as for the fusion reactors. It is found that radwaste from the fusion reactors using F82H and SiC/SiC composites without impurities could be disposed by the shallow land disposal presently applied to the low level waste in Japan. The disposal cost of radwaste from five fusion power reactors and a typical light water reactor were roughly evaluated and compared.

TALE-PvuII Fusion Proteins – Novel Tools for Gene Targeting

PubMed Central

Yanik, Mert; Alzubi, Jamal; Lahaye, Thomas; Cathomen, Toni; Pingoud, Alfred; Wende, Wolfgang

2013-01-01

Zinc finger nucleases (ZFNs) consist of zinc fingers as DNA-binding module and the non-specific DNA-cleavage domain of the restriction endonuclease FokI as DNA-cleavage module. This architecture is also used by TALE nucleases (TALENs), in which the DNA-binding modules of the ZFNs have been replaced by DNA-binding domains based on transcription activator like effector (TALE) proteins. Both TALENs and ZFNs are programmable nucleases which rely on the dimerization of FokI to induce double-strand DNA cleavage at the target site after recognition of the target DNA by the respective DNA-binding module. TALENs seem to have an advantage over ZFNs, as the assembly of TALE proteins is easier than that of ZFNs. Here, we present evidence that variant TALENs can be produced by replacing the catalytic domain of FokI with the restriction endonuclease PvuII. These fusion proteins recognize only the composite recognition site consisting of the target site of the TALE protein and the PvuII recognition sequence (addressed site), but not isolated TALE or PvuII recognition sites (unaddressed sites), even at high excess of protein over DNA and long incubation times. In vitro, their preference for an addressed over an unaddressed site is > 34,000-fold. Moreover, TALE-PvuII fusion proteins are active in cellula with minimal cytotoxicity. PMID:24349308

Gamete donors' satisfaction; gender differences and similarities among oocyte and sperm donors in a national sample

PubMed Central

Svanberg, Agneta Skoog; Lampic, Claudia; Gejerwall, Ann-Louise; Gudmundsson, Johannes; Karlström, Per-olof; Solensten, Nils-Gunnar; Sydsjö, Gunilla

2013-01-01

ObjectiveTo explore oocyte and sperm donors' emotional stress, experiences of care and satisfaction after donation. DesignProspective multicenter study. SettingsAll fertility clinics performing gamete donation in Sweden during the period 2005 to 2008. PopulationOf 220 eligible oocyte donors who were approached, 181 agreed to complete the first questionnaire and 165 completed the second questionnaire 2 months after oocyte donation. Of 156 eligible sperm donors 119 accepted to complete the first questionnaire before donation. Eighty-nine participants completed the second questionnaire 2 months after sperm donation. MethodsStandardized and study-specific questionnaires. Main outcome measuresSatisfaction with the donation, respondents' mental health and overall care. ResultsA larger percentage of sperm donors (97.8%) were satisfied with their overall experience of being a donor than oocyte donors (85.9%, p = 0.003). Some oocyte and sperm donors did not receive sufficient information about practical issues (9.1% and 13.5%, respectively) and future consequences (12.8% and 3.4%, respectively, p = 0.014). The donors' symptoms of anxiety and depression did not show any differences in relation to negative or positive perceptions of satisfaction. The donors who did not indicate ambivalence before treatment were on average almost five times more satisfied compared with those who did indicate ambivalence (odds ratio 4.71; 95% CI 1.34–16.51). ConclusionsMost donors were satisfied with their contribution after the donation. Oocyte and sperm donors who expressed ambivalence before donation were less satisfied after donation. In vitro fertilization staff fulfilled most of the donors' needs for information and care. Please cite this article as: Skoog Svanberg A, Lampic C, Gejerwall A-L, Gudmundsson J, Karlström P-O, Solensten N-G, Sydsjö G. Gamete donors’ satisfaction; gender differences and similarities among oocyte and sperm donors in a national sample. Acta

Fusion and erosion of cell walls during confugation in the fussion yeast (Schizosaccharomyces pombe).

PubMed

Calleja, G B; Yoo, B Y; Johnson, B F

1977-06-01

Conjugation in Schizosaccharomyces pombe was studied by transmission electron microscopy. Mural and nuclear events were scored from induction, the initial event, to meiosis I, the start of sporulation. These morphogenic markers were separately identifiable as flocculation, copulation, conjugation-tube formation, cross-wall formation, cross-wall erosion, conjugation-tube expansion, cytoplasmic fusion, de-differentiation of site of union, nuclear migration and karyogamy. The following were identified as new structural elements: sex hairs, which presumably mediate hydrogen bonding between cells during flocculation; crimp at the site of union; dark patch, which presumably serves as a leak-proof seal at the time of cross-wall erosion; suture, an electron-dense seam formed by the union of a copulant pair; and small electron-dense particles close to the site of wall erosion. No special structures on the cell wall could be identified as indicative of specific sites for potential copulatory activity. The discontinuity of the 2 cell walls at the site of union became so de-differentiated after fusion and erosion that it was no longer possible to pinpoint the site of union.

Regulating Gamete Donation in the U.S.: Ethical, Legal and Social Implications

PubMed Central

Sabatello, Maya

2015-01-01

This article explores the practice of gamete donation in the U.S. having in mind the larger question of what do we as a society owe children born as a result (donor-conceived children). Do recipient-parents have a duty to tell their donor-conceived child about his/her genetic origins? Should the identity of the donor be disclosed or remain anonymous? Does the child have a right to know her conception story and to receive information, including identifying information, about the donor? Furthermore, if a donor-conceived child has a right to know, who has the duty to tell her/him about it? The Article underscores the ethical, legal and social dilemmas that arise, comparing and contrasting with international developments in this arena. It highlights the market-based and more specific medical justifications for regulating this field, explores the emerging so-called right of the child to know his/her genetic origins (“the right to know”), and considers the challenges such a right evokes to existing legal culture and principles of medical ethics in the U.S. as well as other broader societal implications of such a right. PMID:26388996

Regulating Gamete Donation in the U.S.: Ethical, Legal and Social Implications.

PubMed

Sabatello, Maya

2015-09-01

This article explores the practice of gamete donation in the U.S. having in mind the larger question of what do we as a society owe children born as a result (donor-conceived children). Do recipient-parents have a duty to tell their donor-conceived child about his/her genetic origins? Should the identity of the donor be disclosed or remain anonymous? Does the child have a right to know her conception story and to receive information, including identifying information, about the donor? Furthermore, if a donor-conceived child has a right to know, who has the duty to tell her/him about it? The Article underscores the ethical, legal and social dilemmas that arise, comparing and contrasting with international developments in this arena. It highlights the market-based and more specific medical justifications for regulating this field, explores the emerging so-called right of the child to know his/her genetic origins ("the right to know"), and considers the challenges such a right evokes to existing legal culture and principles of medical ethics in the U.S. as well as other broader societal implications of such a right.

Water consumption and biomass production of protoplast fusion lines of poplar hybrids under drought stress

PubMed Central

Hennig, Anne; Kleinschmit, Jörg R. G.; Schoneberg, Sebastian; Löffler, Sonja; Janßen, Alwin; Polle, Andrea

2015-01-01

Woody crops such as poplars (Populus) can contribute to meet the increasing energy demand of a growing human population and can therefore enhance the security of energy supply. Using energy from biomass increases ecological sustainability as biomass is considered to play a pivotal role in abating climate change. Because areas for establishing poplar plantations are often confined to marginal sites drought tolerance is one important trait for poplar genotypes cultivated in short rotation coppice. We tested 9-month-old plants of four tetraploid Populus tremula (L.) × P. tremuloides (Michx.) lines that were generated by protoplast fusion and their diploid counterpart for water consumption and drought stress responses in a greenhouse experiment. The fusion lines showed equivalent or decreased height growth, stem biomass and total leaf area compared to the diploid line. The relative height increment of the fusion lines was not reduced compared to the diploid line when the plants were exposed to drought. The fusion lines were distinguished from the diploid counterpart by stomatal characteristics such as increased size and lower density. The changes in the stomatal apparatus did not affect the stomatal conductance. When exposed to drought the carbohydrate concentrations increased more strongly in the fusion lines than in the diploid line. Two fusion lines consumed significantly less water with regard to height growth, producing equivalent or increased relative stem biomass under drought compared to their diploid relative. Therefore, these tetraploid fusion lines are interesting candidates for short rotation biomass plantation on dry sites. PMID:26042130

Antigenic Fingerprinting following Primary RSV Infection in Young Children Identifies Novel Antigenic Sites and Reveals Unlinked Evolution of Human Antibody Repertoires to Fusion and Attachment Glycoproteins

PubMed Central

Fuentes, Sandra; Coyle, Elizabeth M.; Beeler, Judy; Golding, Hana; Khurana, Surender

2016-01-01

Respiratory Syncytial Virus (RSV) is the major cause of pneumonia among infants. Here we elucidated the antibody repertoire following primary RSV infection and traced its evolution through adolescence and adulthood. Whole genome-fragment phage display libraries (GFPDL) expressing linear and conformational epitopes in the RSV fusion protein (F) and attachment protein (G) were used for unbiased epitope profiling of infant sera prior to and following RSV infection. F-GFPDL analyses demonstrated modest changes in the anti-F epitope repertoires post-RSV infection, while G-GFPDL analyses revealed 100-fold increase in number of bound phages. The G-reactive epitopes spanned the N- and C-terminus of the G ectodomain, along with increased reactivity to the central conserved domain (CCD). Panels of F and G antigenic sites were synthesized to evaluate sera from young children (<2 yr), adolescents (14–18 yr) and adults (30–45 yr) in SPR real-time kinetics assays. A steady increase in RSV-F epitope repertoires from young children to adults was observed using peptides and F proteins. Importantly, several novel epitopes were identified in pre-fusion F and an immunodominant epitope in the F-p27. In all age groups, antibody binding to pre-fusion F was 2–3 folds higher than to post-fusion form. For RSV-G, antibody responses were high following early RSV infection in children, but declined significantly in adults, using either G proteins or peptides. This study identified unlinked evolution of anti-F and anti G responses and supportive evidence for immune pressure driven evolution of RSV-G. These findings could help development of effective countermeasures including vaccines. PMID:27100289

The SARS-CoV Fusion Peptide Forms an Extended Bipartite Fusion Platform that Perturbs Membrane Order in a Calcium-Dependent Manner.

PubMed

Lai, Alex L; Millet, Jean K; Daniel, Susan; Freed, Jack H; Whittaker, Gary R

2017-12-08

Coronaviruses (CoVs) are a major infectious disease threat and include the pathogenic human pathogens of zoonotic origin: severe acute respiratory syndrome CoV (SARS-CoV) and Middle East respiratory syndrome CoV (MERS-CoV). Entry of CoVs into host cells is mediated by the viral spike (S) protein, which is structurally categorized as a class I viral fusion protein, within the same group as influenza virus and HIV. However, S proteins have two distinct cleavage sites that can be activated by a much wider range of proteases. The exact location of the CoV fusion peptide (FP) has been disputed. However, most evidence suggests that the domain immediately downstream of the S2' cleavage site is the FP (amino acids 798-818 SFIEDLLFNKVTLADAGFMKQY for SARS-CoV, FP1). In our previous electron spin resonance spectroscopic studies, the membrane-ordering effect of influenza virus, HIV, and Dengue virus FPs has been consistently observed. In this study, we used this effect as a criterion to identify and characterize the bona fide SARS-CoV FP. Our results indicate that both FP1 and the region immediately downstream (amino acids 816-835 KQYGECLGDINARDLICAQKF, FP2) induce significant membrane ordering. Furthermore, their effects are calcium dependent, which is consistent with in vivo data showing that calcium is required for SARS-CoV S-mediated fusion. Isothermal titration calorimetry showed a direct interaction between calcium cations and both FPs. This Ca 2+ -dependency membrane ordering was not observed with influenza FP, indicating that the CoV FP exhibits a mechanistically different behavior. Membrane-ordering effects are greater and penetrate deeper into membranes when FP1 and FP2 act in a concerted manner, suggesting that they form an extended fusion "platform." Copyright © 2017 Elsevier Ltd. All rights reserved.

Spermatological characters of the pseudophyllidean cestode Bothriocephalus scorpii (Müller, 1776).

PubMed

Levron, Céline; Brunanská, Magdaléna; Poddubnaya, Larisa G

2006-06-01

Spermiogenesis of Bothriocephalus scorpii (Cestoda, Pseudophyllidea) includes an orthogonal development of two flagella, followed by a flagellar rotation and a proximo-distal fusion with the median cytoplasmic process. The fusion occurs at the level of four attachment zones. The presence of dense material in the apical region of the differentiation zone in the early stage of spermiogenesis appears to be a characteristic feature for the Pseudophyllidea. The mature spermatozoon possesses two axonemes of 9+"1" pattern of the Trepaxonemata, nucleus, cortical microtubules, electron-dense granules and crested body. The anterior part of the gamete exhibits a centriole surrounded by electron-dense tubular structures arranged as incomplete spiral. When the crested body disappears, the electron-dense tubular structures are arranged into a ring encircling the axoneme. The electron-dense tubular structures and their arrangement appear to be a specific feature for the clade "Bothriocephalidea". The organization of the posterior extremity of the gamete with the nucleus is described for the first time in the Pseudophyllidea.

LaSota fusion (F) cleavage motif-mediated fusion activity is affected by other regions of the F protein from different genotype Newcastle disease virus in a chimeric virus: implication for virulence attenuation.

PubMed

Kim, Shin-Hee; Xiao, Sa; Collins, Peter L; Samal, Siba K

2016-06-01

The cleavage site sequence of the fusion (F) protein contributes to a wide range of virulence of Newcastle disease virus (NDV). In this study, we identified other important amino acid sequences of the F protein that affect cleavage and modulation of fusion. We generated chimeric Beaudette C (BC) viruses containing the cleavage site sequence of avirulent strain LaSota (Las-Fc) together with various regions of the F protein of another virulent strain AKO. We found that the F1 subunit is important for cleavage inhibition. Further dissection of the F1 subunit showed that replacement of four amino acids in the BC/Las-Fc protein with their AKO counterparts (T341S, M384I, T385A and I386L) resulted in an increase in fusion and replication in vitro. In contrast, the mutation N403D greatly reduced cleavage and viral replication, and affected protein conformation. These findings will be useful in developing improved live NDV vaccines and vaccine vectors.

Rho GTPase activity modulates paramyxovirus fusion protein-mediated cell-cell fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schowalter, Rachel M.; Wurth, Mark A.; Aguilar, Hector C.

2006-07-05

The paramyxovirus fusion protein (F) promotes fusion of the viral envelope with the plasma membrane of target cells as well as cell-cell fusion. The plasma membrane is closely associated with the actin cytoskeleton, but the role of actin dynamics in paramyxovirus F-mediated membrane fusion is unclear. We examined cell-cell fusion promoted by two different paramyxovirus F proteins in three cell types in the presence of constitutively active Rho family GTPases, major cellular coordinators of actin dynamics. Reporter gene and syncytia assays demonstrated that expression of either Rac1{sup V12} or Cdc42{sup V12} could increase cell-cell fusion promoted by the Hendra ormore » SV5 glycoproteins, though the effect was dependent on the cell type expressing the viral glycoproteins. In contrast, RhoA{sup L63} decreased cell-cell fusion promoted by Hendra glycoproteins but had little affect on SV5 F-mediated fusion. Also, data suggested that GTPase activation in the viral glycoprotein-containing cell was primarily responsible for changes in fusion. Additionally, we found that activated Cdc42 promoted nuclear rearrangement in syncytia.« less

Keeping mum about dad: "contracts" to protect gamete donor anonymity.

PubMed

Rees, Anne

2012-06-01

This article considers the legal status of so-called contracts for anonymity between fertility clinics and donors of gametes that were made in the period before legislation authorising disclosure. It notes that while clinics frequently cite the existence of these "contracts" to argue against retrospective legislation authorising disclosure of the donor's identity, they may be nothing more than one-sided statements of informed consent. However, the article notes that even if an agreement between a donor and a clinic is not contractual, it does not follow that a person conceived through assisted reproductive technology has any right of access to the identity of the donor. The writer has not been able to locate examples of written promises by the clinics promising anonymity. There are written promises by the donors not to seek the identity of the recipients. These promises do not bind the resulting offspring nor do they appear to be supported by consideration. The article suggests that the basis for any individual donor to restrain a clinic from revealing their identity may be found in promissory estoppel. Nevertheless, there is no real issue in Australia concerning clinics revealing these details absent legislative authority. The issue is whether parliaments will legislate to authorise the disclosure. The article notes that it would be rare for parliaments to legislate to overturn existing legal contracts but suggests that the contract argument may not be as strong as has been thought.

Autograft versus Allograft for Cervical Spinal Fusion: A Systematic Review.

PubMed

Tuchman, Alexander; Brodke, Darrel S; Youssef, Jim A; Meisel, Hans-Jörg; Dettori, Joseph R; Park, Jong-Beom; Yoon, S Tim; Wang, Jeffrey C

2017-02-01

Systematic review. To compare the effectiveness and safety between iliac crest bone graft (ICBG), non-ICBG autologous bone, and allograft in cervical spine fusion. To avoid problems at the donor site, various allograft materials have been used as a substitute for autograft. However, there are still questions as to the comparative effectiveness and safety of cadaver allograft compared with autologous ICBG. A systematic search of multiple major medical reference databases was conducted to identify studies evaluating spinal fusion in patients with cervical degenerative disk disease using ICBG compared with non-ICBG autograft or allograft or non-ICBG autograft compared with allograft in the cervical spine. Radiographic fusion, patient-reported outcomes, and functional outcomes were the primary outcomes of interest. Adverse events were evaluated for safety. The search identified 13 comparative studies that met our inclusion criteria: 2 prospective cohort studies and 11 retrospective cohort studies. Twelve cohort studies compared allograft with ICBG autograft during anterior cervical fusion and demonstrated with a low evidence level of support that there are no differences in fusion percentages, pain scores, or functional results. There was insufficient evidence comparing patients receiving allograft with non-ICBG autograft for fusion, pain, revision, and functional and safety outcomes. No publications directly comparing non-ICBG autograft with ICBG were found. Although the available literature suggests ICBG and allograft may have similar effectiveness in terms of fusion rates, pain scores, and functional outcomes following anterior cervical fusion, there are too many limitations in the available literature to draw any significant conclusions. No individual study provided greater than class III evidence, and when evaluating the overall body of literature, no conclusion had better than low evidence support. A prospective randomized trial with adequate sample size to

The Fusion Gain Analysis of the Inductively Driven Liner Compression Based Fusion

NASA Astrophysics Data System (ADS)

Shimazu, Akihisa; Slough, John

2016-10-01

An analytical analysis of the fusion gain expected in the inductively driven liner compression (IDLC) based fusion is conducted to identify the fusion gain scaling at various operating conditions. The fusion based on the IDLC is a magneto-inertial fusion concept, where a Field-Reversed Configuration (FRC) plasmoid is compressed via the inductively-driven metal liner to drive the FRC to fusion conditions. In the past, an approximate scaling law for the expected fusion gain for the IDLC based fusion was obtained under the key assumptions of (1) D-T fuel at 5-40 keV, (2) adiabatic scaling laws for the FRC dynamics, (3) FRC energy dominated by the pressure balance with the edge magnetic field at the peak compression, and (4) the liner dwell time being liner final diameter divided by the peak liner velocity. In this study, various assumptions made in the previous derivation is relaxed to study the change in the fusion gain scaling from the previous result of G ml1 / 2 El11 / 8 , where ml is the liner mass and El is the peak liner kinetic energy. The implication from the modified fusion gain scaling on the performance of the IDLC fusion reactor system is also explored.

The chemistry of gamete attraction: chemical structures, biosynthesis, and (a)biotic degradation of algal pheromones.

PubMed Central

Boland, W

1995-01-01

Female gametes of marine brown algae release and/or attract their conspecific males by chemical signals. The majority of these compounds are unsaturated, nonfunctionalized acyclic, and/or alicyclic C11 hydrocarbons. Threshold concentrations for release and attraction are generally observed in the range of 1-1000 pmol. The blends may contain various configurational isomers of the genuine pheromones as well as mixtures of enantiomers. Higher plants produce the C11 hydrocarbons from dodeca-3,6,9-trienoic acid; brown algae exploit the family of icosanoids for biosynthesis of the same compounds. The biosynthetic routes comprise several spontaneously occurring pericyclic reactions such as [3.3]-sigmatropic rearrangements, [1.7]-hydrogen shifts, and electrocyclic ring closures. All pheromones are (a)biotically degraded by ubiquitous oxidative pathways involving singlet oxygen or hydroxyl radicals, which may be produced through the agency of heavy metals, huminic acids, or light. PMID:7816845

Inertial confinement fusion method producing line source radiation fluence

DOEpatents

Rose, Ronald P.

1984-01-01

An inertial confinement fusion method in which target pellets are imploded in sequence by laser light beams or other energy beams at an implosion site which is variable between pellet implosions along a line. The effect of the variability in position of the implosion site along a line is to distribute the radiation fluence in surrounding reactor components as a line source of radiation would do, thereby permitting the utilization of cylindrical geometry in the design of the reactor and internal components.

Novel cooperative neural fusion algorithms for image restoration and image fusion.

PubMed

Xia, Youshen; Kamel, Mohamed S

2007-02-01

To deal with the problem of restoring degraded images with non-Gaussian noise, this paper proposes a novel cooperative neural fusion regularization (CNFR) algorithm for image restoration. Compared with conventional regularization algorithms for image restoration, the proposed CNFR algorithm can relax need of the optimal regularization parameter to be estimated. Furthermore, to enhance the quality of restored images, this paper presents a cooperative neural fusion (CNF) algorithm for image fusion. Compared with existing signal-level image fusion algorithms, the proposed CNF algorithm can greatly reduce the loss of contrast information under blind Gaussian noise environments. The performance analysis shows that the proposed two neural fusion algorithms can converge globally to the robust and optimal image estimate. Simulation results confirm that in different noise environments, the proposed two neural fusion algorithms can obtain a better image estimate than several well known image restoration and image fusion methods.

Magnetic-confinement fusion

NASA Astrophysics Data System (ADS)

Ongena, J.; Koch, R.; Wolf, R.; Zohm, H.

2016-05-01

Our modern society requires environmentally friendly solutions for energy production. Energy can be released not only from the fission of heavy nuclei but also from the fusion of light nuclei. Nuclear fusion is an important option for a clean and safe solution for our long-term energy needs. The extremely high temperatures required for the fusion reaction are routinely realized in several magnetic-fusion machines. Since the early 1990s, up to 16 MW of fusion power has been released in pulses of a few seconds, corresponding to a power multiplication close to break-even. Our understanding of the very complex behaviour of a magnetized plasma at temperatures between 150 and 200 million °C surrounded by cold walls has also advanced substantially. This steady progress has resulted in the construction of ITER, a fusion device with a planned fusion power output of 500 MW in pulses of 400 s. ITER should provide answers to remaining important questions on the integration of physics and technology, through a full-size demonstration of a tenfold power multiplication, and on nuclear safety aspects. Here we review the basic physics underlying magnetic fusion: past achievements, present efforts and the prospects for future production of electrical energy. We also discuss questions related to the safety, waste management and decommissioning of a future fusion power plant.

Histology, fusion status, and outcome in metastatic rhabdomyosarcoma: A report from the Children's Oncology Group.

PubMed

Rudzinski, Erin R; Anderson, James R; Chi, Yueh-Yun; Gastier-Foster, Julie M; Astbury, Caroline; Barr, Frederic G; Skapek, Stephen X; Hawkins, Douglas S; Weigel, Brenda J; Pappo, Alberto; Meyer, William H; Arnold, Michael A; Teot, Lisa A; Parham, David M

2017-12-01

Distinguishing alveolar rhabdomyosarcoma (ARMS) from embryonal rhabdomyosarcoma (ERMS) has historically been of prognostic and therapeutic importance. However, classification has been complicated by shifting histologic criteria required for an ARMS diagnosis. Children's Oncology Group (COG) studies after IRS-IV, which included the height of this diagnostic shift, showed both an increased number of ARMS and an increase in the proportion of fusion-negative ARMS. Following diagnostic standardization and histologic re-review of ARMS cases enrolled during this era, analysis of low-risk (D9602) and intermediate-risk (D9803) rhabdomyosarcoma (RMS) studies showed that fusion status rather than histology best predicts prognosis for patients with RMS. This analysis remains to be completed for patients with high-risk RMS. We re-reviewed cases on high-risk COG studies D9802 and ARST0431 with an enrollment diagnosis of ARMS. We compared the event-free survival (EFS) and overall survival by histology, PAX-FOXO1 fusion, and clinical risk factors (Oberlin score) for patients with metastatic RMS using the log-rank test. Histology re-review resulted in reclassification as ERMS for 12% of D9802 cases and 5% of ARST0431 cases. Fusion-negative RMS had a superior EFS to fusion-positive RMS; however, poorer outcome for metastatic RMS was most related to clinical risk factors including age, primary site, and number of metastatic sites. In contrast to low- or intermediate-risk RMS, in metastatic RMS, clinical risk factors have the most impact on patient outcome. PAX-FOXO1 fusion is more common in patients with a high Oberlin score, but fusion status is not an independent biomarker of prognosis. © 2017 Wiley Periodicals, Inc.

Genetic analysis of heptad-repeat regions in the G2 fusion subunit of the Junin arenavirus envelope glycoprotein

DOE Office of Scientific and Technical Information (OSTI.GOV)

York, Joanne; Agnihothram, Sudhakar S.; Romanowski, Victor

2005-12-20

The G2 fusion subunit of the Junin virus envelope glycoprotein GP-C contains two hydrophobic heptad-repeat regions that are postulated to form a six-helix bundle structure required for the membrane fusion activity of Class I viral fusion proteins. We have investigated the role of these heptad-repeat regions and, specifically, the importance of the putative interhelical a and d position sidechains by using alanine-scanning mutagenesis. All the mutant glycoproteins were expressed and transported to the cell surface. Proteolytic maturation at the subtilisin kexin isozyme-1/site-1-protease (SKI-1/S1P) cleavage site was observed in all but two of the mutants. Among the adequately cleaved mutant glycoproteins,more » four positions in the N-terminal region (I333, L336, L347 and L350) and two positions in the C-terminal region (R392 and W395) were shown to be important determinants of cell-cell fusion. Taken together, our results indicate that {alpha}-helical coiled-coil structures are likely critical in promoting arenavirus membrane fusion. These findings support the inclusion of the arenavirus GP-C among the Class I viral fusion proteins and suggest pharmacologic and immunologic strategies for targeting arenavirus infection and hemorrhagic fever.« less

CONFERENCE REPORT: Summary of the 8th IAEA Technical Meeting on Fusion Power Plant Safety

NASA Astrophysics Data System (ADS)

Girard, J. Ph.; Gulden, W.; Kolbasov, B.; Louzeiro-Malaquias, A.-J.; Petti, D.; Rodriguez-Rodrigo, L.

2008-01-01

Reports were presented covering a selection of topics on the safety of fusion power plants. These included a review on licensing studies developed for ITER site preparation surveying common and non-common issues (i.e. site dependent) as lessons to a broader approach for fusion power plant safety. Several fusion power plant models, spanning from accessible technology to more advanced-materials based concepts, were discussed. On the topic related to fusion-specific technology, safety studies were reported on different concepts of breeding blanket modules, tritium handling and auxiliary systems under normal and accident scenarios' operation. The testing of power plant relevant technology in ITER was also assessed in terms of normal operation and accident scenarios, and occupational doses and radioactive releases under these testings have been determined. Other specific safety issues for fusion have also been discussed such as availability and reliability of fusion power plants, dust and tritium inventories and component failure databases. This study reveals that the environmental impact of fusion power plants can be minimized through a proper selection of low activation materials and using recycling technology helping to reduce waste volume and potentially open the route for its reutilization for the nuclear sector or even its clearance into the commercial circuit. Computational codes for fusion safety have been presented in support of the many studies reported. The on-going work on establishing validation approaches aiming at improving the prediction capability of fusion codes has been supported by experimental results and new directions for development have been identified. Fusion standards are not available and fission experience is mostly used as the framework basis for licensing and target design for safe operation and occupational and environmental constraints. It has been argued that fusion can benefit if a specific fusion approach is implemented, in particular

Postmating sexual conflict and female control over fertilization during gamete interaction.

PubMed

Firman, Renée C

2018-06-01

Males and females rarely have identical evolutionary interests over reproduction, and when the fitness of both sexes is dependent upon paternity outcomes, sexual conflict over fertilization is inevitable. In internal fertilizers, the female tract is a formidable selective force on the number and integrity of sperm that reach the egg. Selection on sperm quality is intensified when females mate multiply and rival males are forced to compete for fertilizations. While male adaptations to sperm competition have been well documented (e.g., increased sperm fertilizing capacity), much less attention has been given to the evolutionary consequences of postmating sexual conflict for egg form and function. Specifically, increased sperm competitiveness can be detrimental by giving rise to an elevation in reproductive failure resulting from polyspermy. Spanning literature on both internal and external fertilizers, in this review I discuss how females respond to sperm competition via fertilization barriers that mediate sperm entry. These findings, which align directly with sexual conflict theory, indicate that females have greater control over fertilization than has previously been appreciated. I then consider the implications of gametic sexual conflict in relation to the development of reproductive isolation and speculate on potential mechanisms accounting for "egg defensiveness." Finally, I discuss the functional significance of egg defensiveness for both the sexes, and sperm selection for females. © 2018 New York Academy of Sciences.

Identification of novel target sites and an inhibitor of the dengue virus E protein.

PubMed

Yennamalli, Ragothaman; Subbarao, Naidu; Kampmann, Thorsten; McGeary, Ross P; Young, Paul R; Kobe, Bostjan

2009-06-01

Dengue and related flaviviruses represent a significant global health threat. The envelope glycoprotein E mediates virus attachment to a host cell and the subsequent fusion of viral and host cell membranes. The fusion process is driven by conformational changes in the E protein and is an essential step in the virus life cycle. In this study, we analyzed the pre-fusion and post-fusion structures of the dengue virus E protein to identify potential novel sites that could bind small molecules, which could interfere with the conformational transitions that mediate the fusion process. We used an in silico virtual screening approach combining three different docking algorithms (DOCK, GOLD and FlexX) to identify compounds that are likely to bind to these sites. Seven structurally diverse molecules were selected to test experimentally for inhibition of dengue virus propagation. The best compound showed an IC(50) in the micromolar range against dengue virus type 2.

Identification of novel target sites and an inhibitor of the dengue virus E protein

NASA Astrophysics Data System (ADS)

Yennamalli, Ragothaman; Subbarao, Naidu; Kampmann, Thorsten; McGeary, Ross P.; Young, Paul R.; Kobe, Bostjan

2009-06-01

Dengue and related flaviviruses represent a significant global health threat. The envelope glycoprotein E mediates virus attachment to a host cell and the subsequent fusion of viral and host cell membranes. The fusion process is driven by conformational changes in the E protein and is an essential step in the virus life cycle. In this study, we analyzed the pre-fusion and post-fusion structures of the dengue virus E protein to identify potential novel sites that could bind small molecules, which could interfere with the conformational transitions that mediate the fusion process. We used an in silico virtual screening approach combining three different docking algorithms (DOCK, GOLD and FlexX) to identify compounds that are likely to bind to these sites. Seven structurally diverse molecules were selected to test experimentally for inhibition of dengue virus propagation. The best compound showed an IC50 in the micromolar range against dengue virus type 2.

FuzzyFusion: an application architecture for multisource information fusion

NASA Astrophysics Data System (ADS)

Fox, Kevin L.; Henning, Ronda R.

2009-04-01

The correlation of information from disparate sources has long been an issue in data fusion research. Traditional data fusion addresses the correlation of information from sources as diverse as single-purpose sensors to all-source multi-media information. Information system vulnerability information is similar in its diversity of sources and content, and in the desire to draw a meaningful conclusion, namely, the security posture of the system under inspection. FuzzyFusionTM, A data fusion model that is being applied to the computer network operations domain is presented. This model has been successfully prototyped in an applied research environment and represents a next generation assurance tool for system and network security.

Role of the Calcium-Sensing Receptor (CaSR) in bovine gametes and during in vitro fertilization.

PubMed

Macías-García, Beatriz; Lopes, Graça; Rocha, Antonio; González-Fernández, Lauro

2017-06-01

Calcium Sensing Receptor (CaSR) is a G-protein coupled receptor which senses extracellular calcium and activates diverse intracellular pathways. The objective of our work was to demonstrate the presence of CaSR in bovine gametes and its possible role in fertilization and embryo development. The location of CaSR was demonstrated by immunofluorescence in bovine gametes; additionally bovine sperm were incubated with 5, 10 and 15 μM of the specific CaSR inhibitor NPS2143 in a Tyrode's Albumin Lactate Pyruvate medium (4 h). Sperm viability was maintained for all concentrations tested while total motility decreased significantly at 10 and 15 μM. Addition of 15 μM of NPS2143 during oocyte in vitro maturation did not alter the maturation rate. When NPS2143 (15 μM) was added to the fertilization medium during sperm-oocyte co-incubation the cleavage, morula and blastocyst rates remained unchanged. To confirm if 15 μM of NPS2143 exerted any effect on embryo development, NPS2143 was added to the embryo culture medium. Cleavage rates remained unchanged when 15 μM of NPS2143 was added to the culture medium (79.1 ± 6.8 vs. 73.7 ± 5.3; mean % ± SEM; p > 0.05, control vs. inhibitor). By contrast, development to the morula (46.6 ± 7.3 vs. 24.3 ± 4.3; mean % ± SEM; p < 0.05) and blastocyst stages (29.9 ± 9.0 vs. 9.9 ± 3.6; mean % ± SEM; p < 0.05) decreased (control vs. inhibitor). Our results demonstrate a key role of CaSR on sperm motility and embryo development but not on oocyte maturation or fertilization in the bovine species. Copyright © 2017 Elsevier Inc. All rights reserved.

Solid radiographic fusion with a nonconstrained device 5 years after cervical arthroplasty.

PubMed

Heary, Robert F; Goldstein, Ira M; Getto, Katarzyna M; Agarwal, Nitin

2014-12-01

Cervical disc arthroplasty (CDA) has been gaining popularity as a surgical alternative to anterior cervical discectomy and fusion. Spontaneous fusion following a CDA is uncommon. A few anecdotal reports of heterotrophic ossification around the implant sites have been noted for the BRYAN, ProDisc-C, Mobi-C, PRESTIGE, and PCM devices. All CDA fusions reported to date have been in devices that are semiconstrained. The authors reported the case of a 56-year-old man who presented with left C-7 radiculopathy and neck pain for 10 weeks after an assault injury. There was evidence of disc herniation at the C6-7 level. He was otherwise healthy with functional scores on the visual analog scale (VAS, 4.2); neck disability index (NDI, 16); and the 36-item short form health survey (SF-36; physical component summary [PSC] score 43 and mental component summary [MCS] score 47). The patient underwent total disc replacement in which the DISCOVER Artificial Cervical Disc (DePuy Spine, Inc.) was used. The patient was seen at regular follow-up visits up to 60 months. At his 60-month follow-up visit, he had complete radiographic fusion at the C6-7 level with bridging trabecular bone and no motion at the index site on dynamic imaging. He was pain free, with a VAS score of 0, NDI score of 0, and SF-36 PCS and MCS scores of 61 and 55, respectively. Conclusions This is the first case report that identifies the phenomenon of fusion around a nonconstrained cervical prosthesis. Despite this unwanted radiographic outcome, the patient's clinical outcome was excellent.

Fusion mutants of Newcastle disease virus selected with monoclonal antibodies to the hemagglutinin-neuraminidase.

PubMed Central

Iorio, R M; Glickman, R L

1992-01-01

The Australia-Victoria (AV) isolate of Newcastle disease virus (NDV) induces fusion from within but not fusion from without. L1, a neuraminidase (NA)-deficient virus derived from AV, has the opposite fusion phenotype from the wild-type virus. It fails to induce the former mode of fusion, but has gained a limited ability to promote the latter. Monoclonal antibodies to antigenic site 23 on the hemagglutinin-neuraminidase (HN) glycoprotein have previously been shown to select variants of the AV isolate that have altered NA activity or receptor-binding affinity. By using an antibody to this site, variants of L1 have been selected. Three of the variants have gained an increased affinity for sialic acid-containing receptors, as evidenced by the resistance of their hemagglutinating activity to the presence of reduced amounts of sialic acid on the surface of chicken erythrocytes. All four variants still have very low levels of NA activity, comparable to that of the parent virus, L1. The alteration in receptor-binding affinity results in a decreased potential for elution from cellular receptors and correlates with an increased ability to promote both modes of fusion. A single amino acid substitution in the HN protein of each variant, responsible for its escape from neutralization, has been identified. These studies identify two HN residues, 193 and 203, at which monoclonal antibody-selected substitution influences the receptor recognition properties of NDV and may influence its ability to promote syncytium formation. Images PMID:1404607

Hendra virus fusion protein transmembrane domain contributes to pre-fusion protein stability

PubMed Central

Webb, Stacy; Nagy, Tamas; Moseley, Hunter; Fried, Michael; Dutch, Rebecca

2017-01-01

Enveloped viruses utilize fusion (F) proteins studding the surface of the virus to facilitate membrane fusion with a target cell membrane. Fusion of the viral envelope with a cellular membrane is required for release of viral genomic material, so the virus can ultimately reproduce and spread. To drive fusion, the F protein undergoes an irreversible conformational change, transitioning from a metastable pre-fusion conformation to a more thermodynamically stable post-fusion structure. Understanding the elements that control stability of the pre-fusion state and triggering to the post-fusion conformation is important for understanding F protein function. Mutations in F protein transmembrane (TM) domains implicated the TM domain in the fusion process, but the structural and molecular details in fusion remain unclear. Previously, analytical ultracentrifugation was utilized to demonstrate that isolated TM domains of Hendra virus F protein associate in a monomer-trimer equilibrium (Smith, E. C., Smith, S. E., Carter, J. R., Webb, S. R., Gibson, K. M., Hellman, L. M., Fried, M. G., and Dutch, R. E. (2013) J. Biol. Chem. 288, 35726–35735). To determine factors driving this association, 140 paramyxovirus F protein TM domain sequences were analyzed. A heptad repeat of β-branched residues was found, and analysis of the Hendra virus F TM domain revealed a heptad repeat leucine-isoleucine zipper motif (LIZ). Replacement of the LIZ with alanine resulted in dramatically reduced TM-TM association. Mutation of the LIZ in the whole protein resulted in decreased protein stability, including pre-fusion conformation stability. Together, our data suggest that the heptad repeat LIZ contributed to TM-TM association and is important for F protein function and pre-fusion stability. PMID:28213515

Structural basis of influenza virus fusion inhibition by the antiviral drug Arbidol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadam, Rameshwar U.; Wilson, Ian A.

The broad-spectrum antiviral drug Arbidol shows efficacy against influenza viruses by targeting the hemagglutinin (HA) fusion machinery. However, the structural basis of the mechanism underlying fusion inhibition by Arbidol has remained obscure, thereby hindering its further development as a specific and optimized influenza therapeutic. We determined crystal structures of Arbidol in complex with influenza virus HA from pandemic 1968 H3N2 and recent 2013 H7N9 viruses. Arbidol binds in a hydrophobic cavity in the HA trimer stem at the interface between two protomers. This cavity is distal to the conserved epitope targeted by broadly neutralizing stem antibodies and is ~16 Åmore » from the fusion peptide. Arbidol primarily makes hydrophobic interactions with the binding site but also induces some conformational rearrangements to form a network of inter- and intraprotomer salt bridges. By functioning as molecular glue, Arbidol stabilizes the prefusion conformation of HA that inhibits the large conformational rearrangements associated with membrane fusion in the low pH of the endosome. This unique binding mode compared with the small-molecule inhibitors of other class I fusion proteins enhances our understanding of how small molecules can function as fusion inhibitors and guides the development of broad-spectrum therapeutics against influenza virus.« less

Muon Catalyzed Fusion

NASA Technical Reports Server (NTRS)

Armour, Edward A.G.

2007-01-01

Muon catalyzed fusion is a process in which a negatively charged muon combines with two nuclei of isotopes of hydrogen, e.g, a proton and a deuteron or a deuteron and a triton, to form a muonic molecular ion in which the binding is so tight that nuclear fusion occurs. The muon is normally released after fusion has taken place and so can catalyze further fusions. As the muon has a mean lifetime of 2.2 microseconds, this is the maximum period over which a muon can participate in this process. This article gives an outline of the history of muon catalyzed fusion from 1947, when it was first realised that such a process might occur, to the present day. It includes a description of the contribution that Drachrnan has made to the theory of muon catalyzed fusion and the influence this has had on the author's research.

Hendra virus fusion protein transmembrane domain contributes to pre-fusion protein stability.

PubMed

Webb, Stacy; Nagy, Tamas; Moseley, Hunter; Fried, Michael; Dutch, Rebecca

2017-04-07

Enveloped viruses utilize fusion (F) proteins studding the surface of the virus to facilitate membrane fusion with a target cell membrane. Fusion of the viral envelope with a cellular membrane is required for release of viral genomic material, so the virus can ultimately reproduce and spread. To drive fusion, the F protein undergoes an irreversible conformational change, transitioning from a metastable pre-fusion conformation to a more thermodynamically stable post-fusion structure. Understanding the elements that control stability of the pre-fusion state and triggering to the post-fusion conformation is important for understanding F protein function. Mutations in F protein transmembrane (TM) domains implicated the TM domain in the fusion process, but the structural and molecular details in fusion remain unclear. Previously, analytical ultracentrifugation was utilized to demonstrate that isolated TM domains of Hendra virus F protein associate in a monomer-trimer equilibrium (Smith, E. C., Smith, S. E., Carter, J. R., Webb, S. R., Gibson, K. M., Hellman, L. M., Fried, M. G., and Dutch, R. E. (2013) J. Biol. Chem. 288, 35726-35735). To determine factors driving this association, 140 paramyxovirus F protein TM domain sequences were analyzed. A heptad repeat of β-branched residues was found, and analysis of the Hendra virus F TM domain revealed a heptad repeat leucine-isoleucine zipper motif (LIZ). Replacement of the LIZ with alanine resulted in dramatically reduced TM-TM association. Mutation of the LIZ in the whole protein resulted in decreased protein stability, including pre-fusion conformation stability. Together, our data suggest that the heptad repeat LIZ contributed to TM-TM association and is important for F protein function and pre-fusion stability. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Combining multiple ChIP-seq peak detection systems using combinatorial fusion.

PubMed

Schweikert, Christina; Brown, Stuart; Tang, Zuojian; Smith, Phillip R; Hsu, D Frank

2012-01-01

Due to the recent rapid development in ChIP-seq technologies, which uses high-throughput next-generation DNA sequencing to identify the targets of Chromatin Immunoprecipitation, there is an increasing amount of sequencing data being generated that provides us with greater opportunity to analyze genome-wide protein-DNA interactions. In particular, we are interested in evaluating and enhancing computational and statistical techniques for locating protein binding sites. Many peak detection systems have been developed; in this study, we utilize the following six: CisGenome, MACS, PeakSeq, QuEST, SISSRs, and TRLocator. We define two methods to merge and rescore the regions of two peak detection systems and analyze the performance based on average precision and coverage of transcription start sites. The results indicate that ChIP-seq peak detection can be improved by fusion using score or rank combination. Our method of combination and fusion analysis would provide a means for generic assessment of available technologies and systems and assist researchers in choosing an appropriate system (or fusion method) for analyzing ChIP-seq data. This analysis offers an alternate approach for increasing true positive rates, while decreasing false positive rates and hence improving the ChIP-seq peak identification process.

Sequence motifs and prokaryotic expression of the reptilian paramyxovirus fusion protein

USGS Publications Warehouse

Franke, J.; Batts, W.N.; Ahne, W.; Kurath, G.; Winton, J.R.

2006-01-01

Fourteen reptilian paramyxovirus isolates were chosen to represent the known extent of genetic diversity among this novel group of viruses. Selected regions of the fusion (F) gene were sequenced, analyzed and compared. The F gene of all isolates contained conserved motifs homologous to those described for other members of the family Paramyxoviridae including: signal peptide, transmembrane domain, furin cleavage site, fusion peptide, N-linked glycosylation sites, and two heptad repeats, the second of which (HRB-LZ) had the characteristics of a leucine zipper. Selected regions of the fusion gene of isolate Gono-GER85 were inserted into a prokaryotic expression system to generate three recombinant protein fragments of various sizes. The longest recombinant protein was cleaved by furin into two fragments of predicted length. Western blot analysis with virus-neutralizing rabbit-antiserum against this isolate demonstrated that only the longest construct reacted with the antiserum. This construct was unique in containing 30 additional C-terminal amino acids that included most of the HRB-LZ. These results indicate that the F genes of reptilian paramyxoviruses contain highly conserved motifs typical of other members of the family and suggest that the HRB-LZ domain of the reptilian paramyxovirus F protein contains a linear antigenic epitope. ?? Springer-Verlag 2005.

FusionAnalyser: a new graphical, event-driven tool for fusion rearrangements discovery

PubMed Central

Piazza, Rocco; Pirola, Alessandra; Spinelli, Roberta; Valletta, Simona; Redaelli, Sara; Magistroni, Vera; Gambacorti-Passerini, Carlo

2012-01-01

Gene fusions are common driver events in leukaemias and solid tumours; here we present FusionAnalyser, a tool dedicated to the identification of driver fusion rearrangements in human cancer through the analysis of paired-end high-throughput transcriptome sequencing data. We initially tested FusionAnalyser by using a set of in silico randomly generated sequencing data from 20 known human translocations occurring in cancer and subsequently using transcriptome data from three chronic and three acute myeloid leukaemia samples. in all the cases our tool was invariably able to detect the presence of the correct driver fusion event(s) with high specificity. In one of the acute myeloid leukaemia samples, FusionAnalyser identified a novel, cryptic, in-frame ETS2–ERG fusion. A fully event-driven graphical interface and a flexible filtering system allow complex analyses to be run in the absence of any a priori programming or scripting knowledge. Therefore, we propose FusionAnalyser as an efficient and robust graphical tool for the identification of functional rearrangements in the context of high-throughput transcriptome sequencing data. PMID:22570408

FusionAnalyser: a new graphical, event-driven tool for fusion rearrangements discovery.

PubMed

Piazza, Rocco; Pirola, Alessandra; Spinelli, Roberta; Valletta, Simona; Redaelli, Sara; Magistroni, Vera; Gambacorti-Passerini, Carlo

2012-09-01

Gene fusions are common driver events in leukaemias and solid tumours; here we present FusionAnalyser, a tool dedicated to the identification of driver fusion rearrangements in human cancer through the analysis of paired-end high-throughput transcriptome sequencing data. We initially tested FusionAnalyser by using a set of in silico randomly generated sequencing data from 20 known human translocations occurring in cancer and subsequently using transcriptome data from three chronic and three acute myeloid leukaemia samples. in all the cases our tool was invariably able to detect the presence of the correct driver fusion event(s) with high specificity. In one of the acute myeloid leukaemia samples, FusionAnalyser identified a novel, cryptic, in-frame ETS2-ERG fusion. A fully event-driven graphical interface and a flexible filtering system allow complex analyses to be run in the absence of any a priori programming or scripting knowledge. Therefore, we propose FusionAnalyser as an efficient and robust graphical tool for the identification of functional rearrangements in the context of high-throughput transcriptome sequencing data.

Who gets the gametes? An argument for a points system for fertility patients

PubMed Central

Jenkins, Simon; Ives, Jonathan; Avery, Sue

2017-01-01

Abstract This paper argues that the convention of allocating donated gametes on a ‘first come, first served’ basis should be replaced with an allocation system that takes into account more morally relevant criteria than waiting time. This conclusion was developed using an empirical bioethics methodology, which involved a study of the views of 18 staff members from seven U.K. fertility clinics, and 20 academics, policy‐makers, representatives of patient groups, and other relevant professionals, on the allocation of donated sperm and eggs. Against these views, we consider some nuanced ways of including criteria in a points allocation system. We argue that such a system is more ethically robust than ‘first come, first served’, but we acknowledge that our results suggest that a points system will meet with resistance from those working in the field. We conclude that criteria such as a patient's age, potentially damaging substance use, and parental status should be used to allocate points and determine which patients receive treatment and in what order. These and other factors should be applied according to how they bear on considerations like child welfare, patient welfare, and the effectiveness of the proposed treatment. PMID:29194680

Vertical transmission of Prunus necrotic ringspot virus: hitch-hiking from gametes to seedling.

PubMed

Amari, Khalid; Burgos, Lorenzo; Pallás, Vicente; Sánchez-Pina, Maria Amelia

2009-07-01

The aim of this work was to follow Prunus necrotic ringspot virus (PNRSV) infection in apricot reproductive tissues and transmission of the virus to the next generation. For this, an analysis of viral distribution in apricot reproductive organs was carried out at different developmental stages. PNRSV was detected in reproductive tissues during gametogenesis. The virus was always present in the nucellus and, in some cases, in the embryo sac. Studies within infected seeds at the embryo globular stage revealed that PNRSV infects all parts of the seed, including embryo, endosperm and testa. In the torpedo and bent cotyledon developmental stages, high concentrations of the virus were detected in the testa and endosperm. At seed maturity, PNRSV accumulated slightly more in the embryo than in the cotyledons. In situ hybridization showed the presence of PNRSV RNA in embryos obtained following hand-pollination of virus-free pistils with infected pollen. Interestingly, tissue-printing from fruits obtained from these pistils showed viral RNA in the periphery of the fruits, whereas crosses between infected pistils and infected pollen resulted in a total invasion of the fruits. Taken together, these results shed light on the vertical transmission of PNRSV from gametes to seedlings.

[Research progress in hirudin fusion protein--review].

PubMed

Zhang, Chuan-Ling; Yu, Ai-Ping; Jin, Ji-De; Wu, Chu-Tse

2007-02-01

Natural hirudin extracted from the secretion of medical leech salivary gland is a single-chain peptide containing 65 aminoacid residues with molecular weight of 7000 D, and exists in three isomers of HV1, HV2 and HV3. Hirudin possesses three disulfide bridges forming the structure of core cyclic peptides, which binds to the catalytic site of thrombin so as to inhibit the catalysis of thrombin. Its c-terminus rich in acidic aminoacid residues possesses hydrophilicity, and is free on the molecular surface, and can bind with fibrin recognition site of hirudin. The minimal segment of 12 - 16 C-terminal acidic residues keeps the minimal activity of anti-thrombosis. Thus, hirudin, as a potent and specific inhibitor of thrombin, can be used to protect from and to treat clinically thrombosis. As it has some disadvantages such as short half-life, bleeding side-effect and mono-function, and so on, hirudin has been fused with some other functional proteins in recent years. The obtained fusion proteins can prolong the half life of hirudin, or relieve it bleeding side effect, or bring new functions, such as thrombolysis, inhibiting the platelet aggregation, targeting specifically. The research progress in hirudin fusion protein was summarized in this review.

Mutations in the Fusion Protein of Measles Virus That Confer Resistance to the Membrane Fusion Inhibitors Carbobenzoxy-d-Phe-l-Phe-Gly and 4-Nitro-2-Phenylacetyl Amino-Benzamide

PubMed Central

Ha, Michael N.; Delpeut, Sébastien; Noyce, Ryan S.; Sisson, Gary; Black, Karen M.; Lin, Liang-Tzung; Bilimoria, Darius; Plemper, Richard K.; Privé, Gilbert G.

2017-01-01

ABSTRACT The inhibitors carbobenzoxy (Z)-d-Phe-l-Phe-Gly (fusion inhibitor peptide [FIP]) and 4-nitro-2-phenylacetyl amino-benzamide (AS-48) have similar efficacies in blocking membrane fusion and syncytium formation mediated by measles virus (MeV). Other homologues, such as Z-d-Phe, are less effective but may act through the same mechanism. In an attempt to map the site of action of these inhibitors, we generated mutant viruses that were resistant to the inhibitory effects of Z-d-Phe-l-Phe-Gly. These 10 mutations were localized to the heptad repeat B (HRB) region of the fusion protein, and no changes were observed in the viral hemagglutinin, which is the receptor attachment protein. Mutations were validated in a luciferase-based membrane fusion assay, using transfected fusion and hemagglutinin expression plasmids or with syncytium-based assays in Vero, Vero-SLAM, and Vero-Nectin 4 cell lines. The changes I452T, D458N, D458G/V459A, N462K, N462H, G464E, and I483R conferred resistance to both FIP and AS-48 without compromising membrane fusion. The inhibitors did not block hemagglutinin protein-mediated binding to the target cell. Edmonston vaccine/laboratory and IC323 wild-type strains were equally affected by the inhibitors. Escape mutations were mapped upon a three-dimensional (3D) structure modeled from the published crystal structure of parainfluenzavirus 5 fusion protein. The most effective mutations were situated in a region located near the base of the globular head and its junction with the alpha-helical stalk of the prefusion protein. We hypothesize that the fusion inhibitors could interfere with the structural changes that occur between the prefusion and postfusion conformations of the fusion protein. IMPORTANCE Due to lapses in vaccination worldwide that have caused localized outbreaks, measles virus (MeV) has regained importance as a pathogen. Antiviral agents against measles virus are not commercially available but could be useful in conjunction with Me

A systematic screen for morphological abnormalities during fission yeast sexual reproduction identifies a mechanism of actin aster formation for cell fusion

PubMed Central

Groux, Raphaël; Vincenzetti, Vincent

2017-01-01

In non-motile fungi, sexual reproduction relies on strong morphogenetic changes in response to pheromone signaling. We report here on a systematic screen for morphological abnormalities of the mating process in fission yeast Schizosaccharomyces pombe. We derived a homothallic (self-fertile) collection of viable deletions, which, upon visual screening, revealed a plethora of phenotypes affecting all stages of the mating process, including cell polarization, cell fusion and sporulation. Cell fusion relies on the formation of the fusion focus, an aster-like F-actin structure that is marked by strong local accumulation of the myosin V Myo52, which concentrates secretion at the fusion site. A secondary screen for fusion-defective mutants identified the myosin V Myo51-associated coiled-coil proteins Rng8 and Rng9 as critical for the coalescence of the fusion focus. Indeed, rng8Δ and rng9Δ mutant cells exhibit multiple stable dots at the cell-cell contact site, instead of the single focus observed in wildtype. Rng8 and Rng9 accumulate on the fusion focus, dependent on Myo51 and tropomyosin Cdc8. A tropomyosin mutant allele, which compromises Rng8/9 localization but not actin binding, similarly leads to multiple stable dots instead of a single focus. By contrast, myo51 deletion does not strongly affect fusion focus coalescence. We propose that focusing of the actin filaments in the fusion aster primarily relies on Rng8/9-dependent cross-linking of tropomyosin-actin filaments. PMID:28410370

Germline Defects Caused by Smed-boule RNA-Interference Reveal That Egg Capsule Deposition Occurs Independently of Fertilization, Ovulation, Mating, or the Presence of Gametes in Planarian Flatworms.

PubMed

Steiner, Jessica Kathryne; Tasaki, Junichi; Rouhana, Labib

2016-05-01

Few animals are known to lay eggs in the absence of ovulation or copulation, as it is presumably energetically wasteful and subjected to negative selection. Characterization of Smed-boule, a member of the DAZ family of germline RNA-binding proteins, revealed that egg capsule (or capsule) production and deposition occurs independently of the presence of gametes in the planarian flatworm Schmidtea mediterranea. Reduction of Smed-boule expression by RNA-interference (RNAi) causes ablation of spermatogonial stem cells and the inability of ovarian germline stem cells to undergo oogenesis. Although animals subjected to Smed-boule RNAi lose their gametes and become sterile, they continue to lay egg capsules. Production of sterile capsules is even observed in virgin Smed-boule(RNAi) and control planarians maintained in complete isolation, demonstrating that egg production in S. mediterranea occurs independently of ovulation, fertilization, or mating. Evidence suggests that this is a conserved feature amongst Platyhelminthes, and therefore relevant to the pathology and dissemination of parasitic flatworms. These findings demonstrate that Smed-boule functions at different stages during male and female germline stem cell development, and also demonstrate that egg capsule production by planarian flatworms occurs independently of signals produced by mating or ova.

SERS-activating effect of chlorides on borate-stabilized silver nanoparticles: formation of new reduced adsorption sites and induced nanoparticle fusion.

PubMed

Sloufová, Ivana; Sisková, Karolína; Vlcková, Blanka; Stepánek, Josef

2008-04-28

Changes in morphology, surface reactivity and surface-enhancement of Raman scattering induced by modification of borate-stabilized Ag nanoparticles by adsorbed chlorides have been explored using TEM, EDX analysis and SERS spectra of probing adsorbate 2,2'-bipyridine (bpy) excited at 514.5 nm and evaluated by factor analysis. At fractional coverages of the parent Ag nanoparticles by adsorbed chlorides <0.6, the Ag colloid/Cl(-)/bpy systems were found to be constituted by fractal aggregates of Ag nanoparticles fairly uniform in size (10 +/- 2 nm) and SERS spectra of Ag(+)-bpy surface species were detected. The latter result was interpreted in terms of the presence of oxidized Ag(+) and/or Ag(n)(+) adsorption sites, which have been encountered also in systems with the chemically untreated Ag nanoparticles. At chloride coverages >0.6, a fusion of fractal aggregates into the compact aggregates of touching and/or interpenetrating Ag nanoparticles has been observed and found to be accompanied by the formation of another surface species, Ag-bpy, as well as by the increase of the overall SERS enhancement of bpy by factor of 40. The same Ag-bpy surface species has been detected under the strongly reducing conditions of reduction of silver nitrate by sodium borohydride in the presence of bpy. The formation of Ag-bpy is thus interpreted in terms of the stabilization of reduced Ag(0) adsorption sites by adsorbed bpy. The formation of reduced adsorption sites on Ag nanoparticle surfaces at chloride coverages >0.6 is discussed in terms of local changes in the work function of Ag. Finally, the SERS spectral detection of Ag-bpy species is proposed as a tool for probing the presence of reduced Ag(0) adsorption sites in systems with chemically modified Ag nanoparticles.

Surface apposition and multiple cell contacts promote myoblast fusion in Drosophila flight muscles

PubMed Central

Dhanyasi, Nagaraju; Segal, Dagan; Shimoni, Eyal; Shinder, Vera

2015-01-01

Fusion of individual myoblasts to form multinucleated myofibers constitutes a widely conserved program for growth of the somatic musculature. We have used electron microscopy methods to study this key form of cell–cell fusion during development of the indirect flight muscles (IFMs) of Drosophila melanogaster. We find that IFM myoblast–myotube fusion proceeds in a stepwise fashion and is governed by apparent cross talk between transmembrane and cytoskeletal elements. Our analysis suggests that cell adhesion is necessary for bringing myoblasts to within a minimal distance from the myotubes. The branched actin polymerization machinery acts subsequently to promote tight apposition between the surfaces of the two cell types and formation of multiple sites of cell–cell contact, giving rise to nascent fusion pores whose expansion establishes full cytoplasmic continuity. Given the conserved features of IFM myogenesis, this sequence of cell interactions and membrane events and the mechanistic significance of cell adhesion elements and the actin-based cytoskeleton are likely to represent general principles of the myoblast fusion process. PMID:26459604

Nuclear Fusion prize laudation Nuclear Fusion prize laudation

NASA Astrophysics Data System (ADS)

Burkart, W.

2011-01-01

Clean energy in abundance will be of critical importance to the pursuit of world peace and development. As part of the IAEA's activities to facilitate the dissemination of fusion related science and technology, the journal Nuclear Fusion is intended to contribute to the realization of such energy from fusion. In 2010, we celebrated the 50th anniversary of the IAEA journal. The excellence of research published in the journal is attested to by its high citation index. The IAEA recognizes excellence by means of an annual prize awarded to the authors of papers judged to have made the greatest impact. On the occasion of the 2010 IAEA Fusion Energy Conference in Daejeon, Republic of Korea at the welcome dinner hosted by the city of Daejeon, we celebrated the achievements of the 2009 and 2010 Nuclear Fusion prize winners. Steve Sabbagh, from the Department of Applied Physics and Applied Mathematics, Columbia University, New York is the winner of the 2009 award for his paper: 'Resistive wall stabilized operation in rotating high beta NSTX plasmas' [1]. This is a landmark paper which reports record parameters of beta in a large spherical torus plasma and presents a thorough investigation of the physics of resistive wall mode (RWM) instability. The paper makes a significant contribution to the critical topic of RWM stabilization. John Rice, from the Plasma Science and Fusion Center, MIT, Cambridge is the winner of the 2010 award for his paper: 'Inter-machine comparison of intrinsic toroidal rotation in tokamaks' [2]. The 2010 award is for a seminal paper that analyzes results across a range of machines in order to develop a universal scaling that can be used to predict intrinsic rotation. This paper has already triggered a wealth of experimental and theoretical work. I congratulate both authors and their colleagues on these exceptional papers. W. Burkart Deputy Director General Department of Nuclear Sciences and Applications International Atomic Energy Agency, Vienna

Measuring time of flight of fusion products in an inertial electrostatic confinement fusion device for spatial profiling of fusion reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donovan, D. C.; Boris, D. R.; Kulcinski, G. L.

2013-03-15

A new diagnostic has been developed that uses the time of flight (TOF) of the products from a nuclear fusion reaction to determine the location where the fusion reaction occurred. The TOF diagnostic uses charged particle detectors on opposing sides of the inertial electrostatic confinement (IEC) device that are coupled to high resolution timing electronics to measure the spatial profile of fusion reactions occurring between the two charged particle detectors. This diagnostic was constructed and tested by the University of Wisconsin-Madison Inertial Electrostatic Confinement Fusion Group in the IEC device, HOMER, which accelerates deuterium ions to fusion relevant energies inmore » a high voltage ({approx}100 kV), spherically symmetric, electrostatic potential well [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, T. E. Radel, and A. L. Wehmeyer, Fusion Sci. Technol. 47, 1238 (2005)]. The TOF diagnostic detects the products of D(d,p)T reactions and determines where along a chord through the device the fusion event occurred. The diagnostic is also capable of using charged particle spectroscopy to determine the Doppler shift imparted to the fusion products by the center of mass energy of the fusion reactants. The TOF diagnostic is thus able to collect spatial profiles of the fusion reaction density along a chord through the device, coupled with the center of mass energy of the reactions occurring at each location. This provides levels of diagnostic detail never before achieved on an IEC device.« less

Spinal Fusion

MedlinePlus

... concept of fusion is similar to that of welding in industry. Spinal fusion surgery, however, does not ... bone taken from the patient has a long history of use and results in predictable healing. Autograft ...

One and two level posterior lumbar interbody fusion (PLIF) using an expandable, stand-alone, interbody fusion device: a VariLift® case series

PubMed Central

Barrett-Tuck, Rebecca; Del Monaco, Diana

2017-01-01

Background Surgical interventions such as posterior lumbar interbody fusion (PLIF) with and without posterior instrumentation are often employed in patients with degenerative spinal conditions that fail to respond to conservative medical management. The VariLift® Interbody Fusion System was developed as a stand-alone solution to provide the benefits of an intervertebral fusion device without the requirement of supplemental pedicle screw fixation. Methods In this retrospective case series, 25 patients underwent PLIF with a stand-alone VariLift® expandable interbody fusion device without adjunctive pedicle screw fixation. There were 12 men and 13 women, with a mean age of 57.2 years (range, 33–83 years); single level in 18 patients, 2 levels in 7 patients. Back pain severity was reported as none, mild, moderate, severe and worst imaginable at baseline, 6 and 12 months. Preoperatively, 88% (22 of 25) of patients reported severe back pain. Results All patients experienced symptomatic improvement and, by 12 months postoperatively, 71% (15 of 21) of patients reported only mild residual pain. Overall, pain scores improved significantly from baseline to 12 months (P=0.0002). There were no revision surgeries and fusion was achieved 12 of 13 patients (92%) who returned for a 12-month radiographic follow-up. There were three cases of intractable postsurgical pain which required extended hospitalization or pain management, one wound infection and one case of surgical site dehiscence, both treated and resolved during inpatient hospitalization. Conclusions In this single-physician case series, the VariLift® device used in single or two-level PLIF provided effective symptom relief and produced a high fusion rate without the need for supplemental fixation. PMID:28435912

One and two level posterior lumbar interbody fusion (PLIF) using an expandable, stand-alone, interbody fusion device: a VariLift® case series.

PubMed

Barrett-Tuck, Rebecca; Del Monaco, Diana; Block, Jon E

2017-03-01

Surgical interventions such as posterior lumbar interbody fusion (PLIF) with and without posterior instrumentation are often employed in patients with degenerative spinal conditions that fail to respond to conservative medical management. The VariLift ® Interbody Fusion System was developed as a stand-alone solution to provide the benefits of an intervertebral fusion device without the requirement of supplemental pedicle screw fixation. In this retrospective case series, 25 patients underwent PLIF with a stand-alone VariLift ® expandable interbody fusion device without adjunctive pedicle screw fixation. There were 12 men and 13 women, with a mean age of 57.2 years (range, 33-83 years); single level in 18 patients, 2 levels in 7 patients. Back pain severity was reported as none, mild, moderate, severe and worst imaginable at baseline, 6 and 12 months. Preoperatively, 88% (22 of 25) of patients reported severe back pain. All patients experienced symptomatic improvement and, by 12 months postoperatively, 71% (15 of 21) of patients reported only mild residual pain. Overall, pain scores improved significantly from baseline to 12 months (P=0.0002). There were no revision surgeries and fusion was achieved 12 of 13 patients (92%) who returned for a 12-month radiographic follow-up. There were three cases of intractable postsurgical pain which required extended hospitalization or pain management, one wound infection and one case of surgical site dehiscence, both treated and resolved during inpatient hospitalization. In this single-physician case series, the VariLift ® device used in single or two-level PLIF provided effective symptom relief and produced a high fusion rate without the need for supplemental fixation.

Review of fusion synfuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fillo, J.A.

1980-01-01

Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Depending on design, electric generation efficiencies of approx. 40 to 60% and hydrogen production efficiencies by high-temperature electrolysis of approx. 50 to 65% are projected for fusion reactors using high-temperatures blankets. Fusion/coal symbiotic systems appear economically promising for the first generation of commercial fusion synfuels plants. Coal production requirements and the environmental effects of large-scale coal usage would be greatly reduced by a fusion/coal system. In the long term, there could be a gradual transition to an inexhaustible energy system based solely on fusion.

A comparison of commercially available demineralized bone matrix for spinal fusion.

PubMed

Wang, Jeffrey C; Alanay, A; Mark, Davies; Kanim, Linda E A; Campbell, Pat A; Dawson, Edgar G; Lieberman, Jay R

2007-08-01

In an effort to augment the available grafting material as well as to increase spinal fusion rates, the utilization of a demineralized bone matrix (DBM) as a graft extender or replacement is common. There are several commercially available DBM substances available for use in spinal surgery, each with different amounts of DBM containing osteoinductive proteins. Each product may have different osteoinductivity potential due to different methods of preparation, storage, and donor specifications. The purpose of this study is to prospectively compare the osteoinductive potential of three different commercially available DBM substances in an athymic rodent spinal fusion model and to discuss the reasons of the variability in osteoinductivity. A posterolateral fusion was performed in 72 mature athymic nude female rats. Three groups of 18 rats were implanted with 1 of 3 DBMs (Osteofil, Grafton, and Dynagraft). A fourth group was implanted with rodent autogenous iliac crest bone graft. The rats were sacrificed at 2, 4, 6, and 8 weeks. A dose of 0.3 cm(3) per side (0.6 cm(3)per animal) was used for each substance. Radiographs were taken at 2 weeks intervals until sacrifice. Fusion was determined by radiographs, manual palpation, and histological analysis. The Osteofil substance had the highest overall fusion rate (14/18), and the highest early 4 weeks fusion rate of (4/5). Grafton produced slightly lower fusion rates of (11/17) overall, and lower early 4 weeks fusion rate of (2/5). There was no statistically significant difference between the rate of fusion after implantation of Osteofil and Grafton. None of the sites implanted with Dynagraft fused at any time point (0/17), and there was a significantly lower fusion rate between the Dynagraft and the other two substances at the six-week-time point and for final fusion rate (P = 0.0001, Fischer's exact test). None of the autogenous iliac crest animals fused at any time point. Non-decalcified histology confirmed the presence of

Magneto-Inertial Fusion

DOE PAGES

Wurden, G. A.; Hsu, S. C.; Intrator, T. P.; ...

2015-11-17

In this community white paper, we describe an approach to achieving fusion which employs a hybrid of elements from the traditional magnetic and inertial fusion concepts, called magneto-inertial fusion (MIF). Furthermore, the status of MIF research in North America at multiple institutions is summarized including recent progress, research opportunities, and future plans.

Transfer of intracolonial genetic variability through gametes in Acropora hyacinthus corals

NASA Astrophysics Data System (ADS)

Schweinsberg, M.; González Pech, R. A.; Tollrian, R.; Lampert, K. P.

2014-03-01

In recent years, the new phenomenon of intracolonial genetic variability within a single coral colony has been described. This connotes that coral colonies do not necessarily consist of only a single genotype, but may contain several distinct genotypes. Harboring more than one genotype could improve survival under stressful environmental conditions, e.g., climate change. However, so far it remained unclear whether the intracolonial genetic variability of the adult coral is also present in the gametes. We investigated the occurrence of intracolonial genetic variability in 14 mature colonies of the coral Acropora hyacinthus using eight microsatellite loci. A grid was placed over each colony before spawning, and the emerging egg/sperm bundles were collected separately in each grid. The underlying tissues as well as the egg/sperm bundles were genotyped to determine whether different genotypes were present. Within the 14 mature colonies, we detected 10 colonies with more than one genotype (intracolonial genetic variability). Four out of these 10 mature colonies showed a transfer of different genotypes via the eggs to the next generation. In two out of these four cases, we found additional alleles, and in the two other cases, we found only a subset of alleles in the unfertilized eggs. Our results suggest that during reproduction of A. hyacinthus, more than one genotype per colony is able to reproduce. We discuss the occurrence of different genotypes within a single coral colony and the ability for those to release eggs which are genetically distinct.

Membrane fusion and exocytosis.

PubMed

Jahn, R; Südhof, T C

1999-01-01

Membrane fusion involves the merger of two phospholipid bilayers in an aqueous environment. In artificial lipid bilayers, fusion proceeds by means of defined transition states, including hourglass-shaped intermediates in which the proximal leaflets of the fusing membranes are merged whereas the distal leaflets are separate (fusion stalk), followed by the reversible opening of small aqueous fusion pores. Fusion of biological membranes requires the action of specific fusion proteins. Best understood are the viral fusion proteins that are responsible for merging the viral with the host cell membrane during infection. These proteins undergo spontaneous and dramatic conformational changes upon activation. In the case of the paradigmatic fusion proteins of the influenza virus and of the human immunodeficiency virus, an amphiphilic fusion peptide is inserted into the target membrane. The protein then reorients itself, thus forcing the fusing membranes together and inducing lipid mixing. Fusion of intracellular membranes in eukaryotic cells involves several protein families including SNAREs, Rab proteins, and Sec1/Munc-18 related proteins (SM-proteins). SNAREs form a novel superfamily of small and mostly membrane-anchored proteins that share a common motif of about 60 amino acids (SNARE motif). SNAREs reversibly assemble into tightly packed helical bundles, the core complexes. Assembly is thought to pull the fusing membranes closely together, thus inducing fusion. SM-proteins comprise a family of soluble proteins that bind to certain types of SNAREs and prevent the formation of core complexes. Rab proteins are GTPases that undergo highly regulated GTP-GDP cycles. In their GTP form, they interact with specific proteins, the effector proteins. Recent evidence suggests that Rab proteins function in the initial membrane contact connecting the fusing membranes but are not involved in the fusion reaction itself.

Reduction in surgical site infection with suprafascial intrawound application of vancomycin powder in instrumented posterior spinal fusion: a retrospective case-control study.

PubMed

Haimoto, Shoichi; Schär, Ralph T; Nishimura, Yusuke; Hara, Masahito; Wakabayashi, Toshihiko; Ginsberg, Howard J

2018-05-04

OBJECTIVE Recent studies have demonstrated the efficacy of subfascial intrawound application of vancomycin powder in spine surgery in reducing the rate of surgical site infections (SSIs). However, to date no study has evaluated the efficacy and safety of suprafascial application of vancomycin powder in spine surgery. The purpose of this study was to quantify the rate of SSIs after open instrumented posterior spinal fusion with and without application of suprafascial vancomycin powder and to evaluate the rate of vancomycin powder-related local adverse effects. METHODS The authors conducted a single-center retrospective case-control study of adult patients undergoing open instrumented posterior fusion of the cervical, thoracic, or lumbar spine performed by a single surgeon from January 2010 through December 2016. In March 2013, routine application of 1 g of suprafascial vancomycin powder was started for all cases in addition to standard systemic antibiotic prophylaxis. Baseline demographics and operative data as well as the SSI rates were compared between the study groups. The incidence of vancomycin powder-related adverse effects was analyzed. RESULTS A total of 515 patients (268 in the untreated group and 247 in the treated group) were included in the study. The mean age was significantly higher in the treated group than in the untreated group (58.4 vs 54.4 years, p < 0.01). Operative variables were similar between the study groups. Patients receiving vancomycin powder had a significantly lower infection rate (5.6% in the untreated group vs 0% in the treated group, p < 0.001). No vancomycin powder-related adverse effects were identified in the treated group. CONCLUSIONS Routine application of suprafascial intrawound vancomycin powder in addition to systemic antibiotic prophylaxis is an easy-to-use, safe, and effective strategy for preventing SSIs after instrumented posterior spinal fusion. Suprafascial application of vancomycin powder could be a valuable

Review of the magnetic fusion program by the 1986 ERAB Fusion Panel

NASA Astrophysics Data System (ADS)

Davidson, Ronald C.

1987-09-01

The 1986 ERAB Fusion Panel finds that fusion energy continues to be an attractive energy source with great potential for the future, and that the magnetic fusion program continues to make substantial technical progress. In addition, fusion research advances plasma physics, a sophisticated and useful branch of applied science, as well as technologies important to industry and defense. These factors fully justify the substantial expenditures by the Department of Energy in fusion research and development (R&D). The Panel endorses the overall program direction, strategy, and plans, and recognizes the importance and timeliness of proceeding with a burning plasma experiment, such as the proposed Compact Ignition Tokamak (CIT) experiment.

Junction region of EWS-FLI1 fusion protein has a dominant negative effect in Ewing's sarcoma in vitro.

PubMed

Jully, Babu; Vijayalakshmi, Ramshankar; Gopal, Gopisetty; Sabitha, Kesavan; Rajkumar, Thangarajan

2012-11-12

Ewing's sarcoma is a malignancy characterized by a specific 11:22 chromosomal translocation which generates a novel EWS-FLI1 fusion protein functioning as an aberrant transcription factor. In the present study, we have further characterized the junction region of the EWS-FLI1 fusion protein. In-silico model of EWS-FLI1 fusion protein was analysed for ligand binding sites, and a putative region (amino acid (aa) 251-343 of the type 1 fusion protein) in the vicinity of the fusion junction was cloned and expressed using bacterial expression. The recombinant protein was characterized by Circular Dichroism (CD). We then expressed aa 251-280 ectopically in Ewing's sarcoma cell-line and its effect on cell proliferation, tumorigenicity and expression of EWS-FLI1 target genes were analysed. Our modelling analysis indicated that Junction region (aa 251-343) encompasses potential ligand biding sites in the EWS-FLI1 protein and when expressed in bacteria was present as soluble form. Ectopically expressing this region in Ewing's sarcoma cells inhibited tumorigenicity, and EWS-FLI1 target genes indicating a dominant negative biological effect. Junction region can be exploited further as target for drug development in future to specifically target EWS-FLI1 in Ewing's Sarcoma.

Residue-level resolution of alphavirus envelope protein interactions in pH-dependent fusion.

PubMed

Zeng, Xiancheng; Mukhopadhyay, Suchetana; Brooks, Charles L

2015-02-17

Alphavirus envelope proteins, organized as trimers of E2-E1 heterodimers on the surface of the pathogenic alphavirus, mediate the low pH-triggered fusion of viral and endosomal membranes in human cells. The lack of specific treatment for alphaviral infections motivates our exploration of potential antiviral approaches by inhibiting one or more fusion steps in the common endocytic viral entry pathway. In this work, we performed constant pH molecular dynamics based on an atomic model of the alphavirus envelope with icosahedral symmetry. We have identified pH-sensitive residues that cause the largest shifts in thermodynamic driving forces under neutral and acidic pH conditions for various fusion steps. A series of conserved interdomain His residues is identified to be responsible for the pH-dependent conformational changes in the fusion process, and ligand binding sites in their vicinity are anticipated to be potential drug targets aimed at inhibiting viral infections.

Extraction of the Wichita Fusion Nail after Knee Arthrodesis.

PubMed

Neuts, Ann-Sophie; Lammens, Johan; Stuyck, Jose

2016-01-01

To avoid a new exposition and partial damage of a knee arthrodesis site due to the removal of the Wichita fusion nail (WFN), a new extraction technique was developed, using a femoral osteotomy at the proximal end of the nail. Fixing the osteotomy with an Ilizarov frame offered the possibility to perform an additional correction of length and/or alignment if necessary.

Fertilization Mechanisms in Flowering Plants

PubMed Central

Dresselhaus, Thomas; Sprunck, Stefanie; Wessel, Gary M.

2016-01-01

Compared to the animal kingdom, fertilization is particularly complex in flowering plants (angiosperms). Sperm cells of angiosperms have lost their motility and require transportation as a passive cargo by the pollen tube cell to the egg apparatus (egg cell and accessory synergid cells). Sperm cell release from the pollen tube occurs after intensive communication between the pollen tube cell and the receptive synergid, culminating in the lysis of both interaction partners. Following release of the two sperm cells they interact and fuse with two dimorphic female gametes (egg and central cell) forming the major seed components embryo and endosperm, respectively. This process is known as double fertilization. Here we review the current understanding of the processes of sperm cell reception, gamete interaction, their pre-fertilization activation and fusion as well as the mechanisms plants use to prevent the fusion of egg cells with multiple sperm cells. The role of Ca2+ is highlighted in these various processes and comparisons are drawn between fertilization mechanisms in flowering plants and other eukaryotes including mammals. PMID:26859271

The actin cytoskeleton inhibits pore expansion during PIV5 fusion protein-promoted cell-cell fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wurth, Mark A.; Schowalter, Rachel M.; Smith, Everett Clinton

2010-08-15

Paramyxovirus fusion (F) proteins promote both virus-cell fusion, required for viral entry, and cell-cell fusion, resulting in syncytia formation. We used the F-actin stabilizing drug, jasplakinolide, and the G-actin sequestrant, latrunculin A, to examine the role of actin dynamics in cell-cell fusion mediated by the parainfluenza virus 5 (PIV5) F protein. Jasplakinolide treatment caused a dose-dependent increase in cell-cell fusion as measured by both syncytia and reporter gene assays, and latrunculin A treatment also resulted in fusion stimulation. Treatment with jasplakinolide or latrunculin A partially rescued a fusion pore opening defect caused by deletion of the PIV5 F protein cytoplasmicmore » tail, but these drugs had no effect on fusion inhibited at earlier stages by either temperature arrest or by a PIV5 heptad repeat peptide. These data suggest that the cortical actin cytoskeleton is an important regulator of fusion pore enlargement, an energetically costly stage of viral fusion protein-mediated membrane merger.« less

The actin cytoskeleton inhibits pore expansion during PIV5 fusion protein-promoted cell-cell fusion

PubMed Central

Wurth, Mark A.; Schowalter, Rachel M.; Smith, Everett Clinton; Moncman, Carole L.; Dutch, Rebecca Ellis; McCann, Richard O.

2010-01-01

Paramyxovirus fusion (F) proteins promote both virus-cell fusion, required for viral entry, and cell-cell fusion, resulting in syncytia formation. We used the F-actin stabilizing drug, jasplakinolide, and the G-actin sequestrant, latrunculin A, to examine the role of actin dynamics in cell-cell fusion mediated by the parainfluenza virus 5 (PIV5) F protein. Jasplakinolide treatment caused a dose-dependent increase in cell-cell fusion as measured by both syncytia and reporter gene assays, and latrunculin A treatment also resulted in fusion stimulation. Treatment with jasplakinolide or latrunculin A partially rescued a fusion pore opening defect caused by deletion of the PIV5 F protein cytoplasmic tail, but these drugs had no effect on fusion inhibited at earlier stages by either temperature arrest or by a PIV5 heptad repeat peptide. These data suggest that the cortical actin cytoskeleton is an important regulator of fusion pore enlargement, an energetically costly stage of viral fusion protein-mediated membrane merger. PMID:20537366

Resident CAPS on dense-core vesicles docks and primes vesicles for fusion

PubMed Central

Kabachinski, Greg; Kielar-Grevstad, D. Michelle; Zhang, Xingmin; James, Declan J.; Martin, Thomas F. J.

2016-01-01

The Ca2+-dependent exocytosis of dense-core vesicles in neuroendocrine cells requires a priming step during which SNARE protein complexes assemble. CAPS (aka CADPS) is one of several factors required for vesicle priming; however, the localization and dynamics of CAPS at sites of exocytosis in live neuroendocrine cells has not been determined. We imaged CAPS before, during, and after single-vesicle fusion events in PC12 cells by TIRF micro­scopy. In addition to being a resident on cytoplasmic dense-core vesicles, CAPS was present in clusters of approximately nine molecules near the plasma membrane that corresponded to docked/tethered vesicles. CAPS accompanied vesicles to the plasma membrane and was present at all vesicle exocytic events. The knockdown of CAPS by shRNA eliminated the VAMP-2–dependent docking and evoked exocytosis of fusion-competent vesicles. A CAPS(ΔC135) protein that does not localize to vesicles failed to rescue vesicle docking and evoked exocytosis in CAPS-depleted cells, showing that CAPS residence on vesicles is essential. Our results indicate that dense-core vesicles carry CAPS to sites of exocytosis, where CAPS promotes vesicle docking and fusion competence, probably by initiating SNARE complex assembly. PMID:26700319

A protein disulfide isomerase gene fusion expression system that increases the extracellular productivity of Bacillus brevis.

PubMed

Kajino, T; Ohto, C; Muramatsu, M; Obata, S; Udaka, S; Yamada, Y; Takahashi, H

2000-02-01

We have developed a versatile Bacillus brevis expression and secretion system based on the use of fungal protein disulfide isomerase (PDI) as a gene fusion partner. Fusion with PDI increased the extracellular production of heterologous proteins (light chain of immunoglobulin G, 8-fold; geranylgeranyl pyrophosphate synthase, 12-fold). Linkage to PDI prevented the aggregation of the secreted proteins, resulting in high-level accumulation of fusion proteins in soluble and biologically active forms. We also show that the disulfide isomerase activity of PDI in a fusion protein is responsible for the suppression of the aggregation of the protein with intradisulfide, whereas aggregation of the protein without intradisulfide was prevented even when the protein was fused to a mutant PDI whose two active sites were disrupted, suggesting that another PDI function, such as chaperone-like activity, synergistically prevented the aggregation of heterologous proteins in the PDI fusion expression system.

A Protein Disulfide Isomerase Gene Fusion Expression System That Increases the Extracellular Productivity of Bacillus brevis

PubMed Central

Kajino, Tsutomu; Ohto, Chikara; Muramatsu, Masayoshi; Obata, Shusei; Udaka, Shigezo; Yamada, Yukio; Takahashi, Haruo

2000-01-01

We have developed a versatile Bacillus brevis expression and secretion system based on the use of fungal protein disulfide isomerase (PDI) as a gene fusion partner. Fusion with PDI increased the extracellular production of heterologous proteins (light chain of immunoglobulin G, 8-fold; geranylgeranyl pyrophosphate synthase, 12-fold). Linkage to PDI prevented the aggregation of the secreted proteins, resulting in high-level accumulation of fusion proteins in soluble and biologically active forms. We also show that the disulfide isomerase activity of PDI in a fusion protein is responsible for the suppression of the aggregation of the protein with intradisulfide, whereas aggregation of the protein without intradisulfide was prevented even when the protein was fused to a mutant PDI whose two active sites were disrupted, suggesting that another PDI function, such as chaperone-like activity, synergistically prevented the aggregation of heterologous proteins in the PDI fusion expression system. PMID:10653729

Deciphering the Theobroma cacao self-incompatibility system: from genomics to diagnostic markers for self-compatibility.

PubMed

Lanaud, Claire; Fouet, Olivier; Legavre, Thierry; Lopes, Uilson; Sounigo, Olivier; Eyango, Marie Claire; Mermaz, Benoit; Da Silva, Marcos Ramos; Loor Solorzano, Rey Gaston; Argout, Xavier; Gyapay, Gabor; Ebaiarrey, Herman Ebai; Colonges, Kelly; Sanier, Christine; Rivallan, Ronan; Mastin, Géraldine; Cryer, Nicholas; Boccara, Michel; Verdeil, Jean-Luc; Efombagn Mousseni, Ives Bruno; Peres Gramacho, Karina; Clément, Didier

2017-10-13

Cocoa self-compatibility is an important yield factor and has been described as being controlled by a late gameto-sporophytic system expressed only at the level of the embryo sac. It results in gametic non-fusion and involves several loci. In this work, we identified two loci, located on chromosomes 1 and 4 (CH1 and CH4), involved in cocoa self-incompatibility by two different processes. Both loci are responsible for gametic selection, but only one (the CH4 locus) is involved in the main fruit drop. The CH1 locus acts prior to the gamete fusion step and independently of the CH4 locus. Using fine-mapping and genome-wide association studies, we focused analyses on restricted regions and identified candidate genes. Some of them showed a differential expression between incompatible and compatible reactions. Immunolocalization experiments provided evidence of CH1 candidate genes expressed in ovule and style tissues. Highly polymorphic simple sequence repeat (SSR) diagnostic markers were designed in the CH4 region that had been identified by fine-mapping. They are characterized by a strong linkage disequilibrium with incompatibility alleles, thus allowing the development of efficient diagnostic markers predicting self-compatibility and fruit setting according to the presence of specific alleles or genotypes. SSR alleles specific to self-compatible Amelonado and Criollo varieties were also identified, thus allowing screening for self-compatible plants in cocoa populations. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Ontological Issues in Higher Levels of Information Fusion: User Refinement of the Fusion Process

DTIC Science & Technology

2003-01-01

fusion question, the thing that is separates the Greek We explore the higher-level purpose offusion systems by philosophical questions and modem day...the The Greeks focused on both data fusion and the Fusion02 conference there are common fusion questions philosophical questions of an ontology - the...data World of Visible Things Belief (pistis) fusion - user refinement. The rest of the paper is as Appearances follows: Section 2 details the Greek

Seasonal Variations in the Risk of Reoperation for Surgical Site Infection Following Elective Spinal Fusion Surgery: A Retrospective Study Using the Japanese Diagnosis Procedure Combination Database.

PubMed

Ohya, Junichi; Chikuda, Hirotaka; Oichi, Takeshi; Kato, So; Matsui, Hiroki; Horiguchi, Hiromasa; Tanaka, Sakae; Yasunaga, Hideo

2017-07-15

A retrospective study of data abstracted from the Diagnosis Procedure Combination (DPC) database, a national representative database in Japan. The aim of this study was to examine seasonal variations in the risk of reoperation for surgical site infection (SSI) following spinal fusion surgery. Although higher rates of infection in the summer than in other seasons were thought to be caused by increasing inexperience of new staff, high temperature, and high humidity, no studies have examined seasonal variations in the risk of SSI following spinal fusion surgery in the country where medical staff rotation timing is not in summer season. In Japan, medical staff rotation starts in April. We retrospectively extracted the data of patients who were admitted between July 2010 and March 2013 from the DPC database. Patients were included if they were aged 20 years or older and underwent elective spinal fusion surgery. The primary outcome was reoperation for SSI during hospitalization. We performed multivariate analysis to clarify the risk factors of primary outcome with adjustment for patient background characteristics. We identified 47,252 eligible patients (23,659 male, 23,593 female). The mean age of the patients was 65.4 years (range, 20-101 yrs). Overall, reoperation for SSI occurred in 0.93% of the patients during hospitalization. The risk of reoperation for SSI was significantly higher in April (vs. February; odds ratio, 1.93; 95% confidence interval, 1.09-3.43, P = 0.03) as well as other known risk factors. In subgroup analysis with stratification for type of hospital, month of surgery was identified as an independent risk factor of reoperation for SSI among cases in an academic hospital, although there was no seasonal variation among those in a nonacademic hospital. This study showed that month of surgery is a risk factor of reoperation for SSI following elective spinal fusion surgery, nevertheless, in the country where medical staff rotation timing is not in

Reproductive and therapeutic cloning, germline therapy, and purchase of gametes and embryos: comments on Canadian legislation governing reproduction technologies.

PubMed

Bernier, L; Grégoire, D

2004-12-01

In Canada, the Assisted Human Reproduction Act received royal assent on 29 March 2004. The approach proposed by the federal government responds to Canadians' strong desire for an enforceable legislative framework in the field of reproduction technologies through criminal law. As a result of the widening gap between the rapid pace of technological change and governing legislation, a distinct need was perceived to create a regulatory framework to guide decisions regarding reproductive technologies. In this article the three main topics covered in the new legislation are commented on: cloning, germline therapy, and purchase of gametes and embryos. Some important issues also covered in the new legislation, such as privacy and access to information, data protection, identity of donors, and inspection, will not be addressed.

Technologies for Army Knowledge Fusion

DTIC Science & Technology

2004-09-01

interpret it in context and understand the implications (Alberts et al., 2002). Note that the knowledge / information fusion issue arises immediately here...Army Knowledge Fusion Richard Scherl Department of Computer Science Monmouth University Dana L. Ulery Computational and Information Sciences...civilian and military sources. Knowledge fusion, also called information fusion and multisensor data fusion, names the body of techniques needed to

Arabidopsis female gametophyte gene expression map reveals similarities between plant and animal gametes.

PubMed

Wuest, Samuel E; Vijverberg, Kitty; Schmidt, Anja; Weiss, Manuel; Gheyselinck, Jacqueline; Lohr, Miriam; Wellmer, Frank; Rahnenführer, Jörg; von Mering, Christian; Grossniklaus, Ueli

2010-03-23

The development of multicellular organisms is controlled by differential gene expression whereby cells adopt distinct fates. A spatially resolved view of gene expression allows the elucidation of transcriptional networks that are linked to cellular identity and function. The haploid female gametophyte of flowering plants is a highly reduced organism: at maturity, it often consists of as few as three cell types derived from a common precursor [1, 2]. However, because of its inaccessibility and small size, we know little about the molecular basis of cell specification and differentiation in the female gametophyte. Here we report expression profiles of all cell types in the mature Arabidopsis female gametophyte. Differentially expressed posttranscriptional regulatory modules and metabolic pathways characterize the distinct cell types. Several transcription factor families are overrepresented in the female gametophyte in comparison to other plant tissues, e.g., type I MADS domain, RWP-RK, and reproductive meristem transcription factors. PAZ/Piwi-domain encoding genes are upregulated in the egg, indicating a role of epigenetic regulation through small RNA pathways-a feature paralleled in the germline of animals [3]. A comparison of human and Arabidopsis egg cells for enrichment of functional groups identified several similarities that may represent a consequence of coevolution or ancestral gametic features. 2010 Elsevier Ltd. All rights reserved.

Influence of incomplete fusion on complete fusion at energies above the Coulomb barrier

NASA Astrophysics Data System (ADS)

Shuaib, Mohd; Sharma, Vijay R.; Yadav, Abhishek; Sharma, Manoj Kumar; Singh, Pushpendra P.; Singh, Devendra P.; Kumar, R.; Singh, R. P.; Muralithar, S.; Singh, B. P.; Prasad, R.

2017-10-01

In the present work, excitation functions of several reaction residues in the system 19F+169Tm, populated via the complete and incomplete fusion processes, have been measured using off-line γ-ray spectroscopy. The analysis of excitation functions has been done within the framework of statistical model code pace4. The excitation functions of residues populated via xn and pxn channels are found to be in good agreement with those estimated by the theoretical model code, which confirms the production of these residues solely via complete fusion process. However, a significant enhancement has been observed in the cross-sections of residues involving α-emitting channels as compared to the theoretical predictions. The observed enhancement in the cross-sections has been attributed to the incomplete fusion processes. In order to have a better insight into the onset and strength of incomplete fusion, the incomplete fusion strength function has been deduced. At present, there is no theoretical model available which can satisfactorily explain the incomplete fusion reaction data at energies ≈4-6 MeV/nucleon. In the present work, the influence of incomplete fusion on complete fusion in the 19F+169Tm system has also been studied. The measured cross-section data may be important for the development of reactor technology as well. It has been found that the incomplete fusion strength function strongly depends on the α-Q value of the projectile, which is found to be in good agreement with the existing literature data. The analysis strongly supports the projectile-dependent mass-asymmetry systematics. In order to study the influence of Coulomb effect ({Z}{{P}}{Z}{{T}}) on incomplete fusion, the deduced strength function for the present work is compared with the nearby projectile-target combinations. The incomplete fusion strength function is found to increase linearly with {Z}{{P}}{Z}{{T}}, indicating a strong influence of Coulomb effect in the incomplete fusion reactions.

Shortening gametes co-incubation time improves live birth rate for couples with a history of fragmented embryos.

PubMed

Le Bras, Anne; Hesters, Laetitia; Gallot, Vanessa; Tallet, Cathie; Tachdjian, Gerard; Frydman, Nelly

2017-10-01

Short gamete co-incubation (SGCO) consists in decreasing the duration of contact between oocytes and sperm from the standard overnight insemination (SOI) toward 2 hours. However, the effectiveness of this technique to improve in vitro fertilization and embryo transfer (IVF-ET) outcomes remains controversial. Our study was designed to evaluate the efficiency of SGCO in a poor prognosis population with a history of fragmented embryos defined by the presence of at least 50% of the embryos with more than 25% of cytoplasmic fragments. From January 2010 to January 2014, 97 couples were included in a SGCO protocol. We separated women into 2 subgroups: younger and older than 35 years. Compared to SOI, after SGCO, 2-cell stage embryos were higher in all women (p<0.001) and less fragmented in women over 35 years (p<0.05). On day 2, top quality embryos obtained and transferred were higher with SCGO than with SOI, independently of the age of the women (p<0.001). Moreover, the number of embryos with less than 25% of fragmentation was higher after SGCO than SOI (p<0.001) whereas the number of multinucleated embryos was lower (p<0.001). We observed that after fresh ET, independently of the age of the women, the clinical pregnancy rate was 3 times higher after SGCO than after SOI. However, the live-birth rate was 4 times higher with SGCO than with SOI in women above 35 years but 3 times higher with SGCO than with SOI in women younger than 35 years. The present results indicate that for a particular indication, reducing the time of oocytes and sperm co-incubation may improve IVF-ET outcomes in terms of live-birth rate. AMH: anti mullerian hormone; COC: cumulus-oocytes complex; E2: estradiol; ET: embryo transfer; FET: frozen embryo transfer; FSH: follicle stimulating hormone; GnRH: gonadotrophin releasing hormone; hCG: human chorionic gonadotropin hormone; hMG: human menopausal gonadotropin hormone; IRB: institutional review board; IVF: in vitro fertilization; IVF-ET: in vitro

Cluster-impact fusion, or beam-contaminant fusion? (abstract)a),b)

NASA Astrophysics Data System (ADS)

Lo, Daniel H.; Petrasso, Richard D.; Wenzel, Kevin W.

1992-10-01

Beuhler, Friedlander, and Friedman (BFF) reported anomalously huge D-D fusion rates while bombarding deuterated targets with (D2O)N+ clusters (N˜25-1000) accelerated to ≊325 keV [R. J. Beuhler et al., Phys. Rev. Lett. 63, 1292 (1989); R. J. Beuhler et al., J. Phys. Chem. 94, 7665 (1990)] [i.e., ≊0.3 keV lab energy for D in (D2O)100+]. However, from our analysis of BFF's fusion product spectra, we conclude that their D lab energy was ˜50 keV. Therefore, no gross anomalies exist. Also, from our analysis of the BFF beam-ranging experiments through 500 μg/cm2 of Au, we conclude that light-ion-beam contaminants (e.g., D+ of order 100 keV) have not been ruled out, and are the probable cause of their fusion reactions. This work was supported by LLNL Subcontract B116798, Department of Energy (DOE) Grant No. DE-FG02-91ER54109, DOE Magnetic Fusion Energy Technology Fellowship Program (D. H. Lo), and DOE Fusion Energy Postdoctoral Research Program (Kevin W. Wenzel).

2016 Annual Site Environmental Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Finley, Virginia

This report provides the U.S. Department of Energy (DOE) and the public with information on the level of radioactive and non-radioactive pollutants (if any) that are added to the environment as a result of Princeton Plasma Physics Laboratory’s (PPPL) operations. The results of the 2016 environmental surveillance and monitoring program for PPPL’s are presented and discussed. The report also summarizes environmental initiatives, assessments, and community involvement programs that were undertaken in 2016. PPPL has engaged in fusion energy research since 1951. The vision of the Laboratory is to create innovations to make fusion power a practical reality – a clean,more » alternative energy source. 2016 marked the eighteenth year of National Spherical Torus Experiment and the first year of NSTX-U (Upgrade) operations. The NSTX-U Project is a collaboration among national laboratories, universities, and national and international research institutions and is a major element in the US Fusion Energy Sciences Program. Its design tests the physics principles of spherical torus (ST) plasmas, playing an important role in the development of smaller, more economical fusion reactors. NSTX-U began operations after its first upgrade that installed the new center stack magnets and second neutral beam, which would allow for hotter plasmas and greater field strength to maintain the fusion reaction longer. Due to operational issues with a poloidal coil, NSTX-U operated briefly in 2016. In 2016, PPPL’s radiological environmental monitoring program measured tritium in the air at the NSTX-U Stack and at on -site sampling stations. Using highly sensitive monitors, PPPL is capable of detecting small changes in the ambient levels of tritium. The operation of an in- stack monitor located on D-site is used to demonstrate compliance with the National Emission Standard for Hazardous Air Pollutants (NESHAPs) regulations. Also included in PPPL’s radiological environmental monitoring

Allogeneic mesenchymal precursor cells (MPCs) combined with an osteoconductive scaffold to promote lumbar interbody spine fusion in an ovine model.

PubMed

Wheeler, Donna L; Fredericks, Douglas C; Dryer, Randall F; Bae, Hyun W

2016-03-01

Advances in immunomagnetic cell sorting have enabled isolation and purification of pleuripotent stem cells from marrow aspirates and have expanded stem cell therapies to include allogeneic sources. This study aimed to determine the safety and efficacy of allogeneic mesenchymal precursor cells (MPCs) combined with an osteoconductive scaffold in lumbar interbody spinal fusion using an ovine model. Thirty-two skeletally mature ewes underwent a single-level interbody fusion procedure using a Polyetheretherketone fusion cage supplemented with either iliac crest autograft (AG) or an osteconductive scaffold (Mastergraft Matrix, Medtronic, Memphis, TN, USA) with 2.5×10(6) MPCs, 6.25×10(6) MPCs, or 12.5×10(6) MPCs. Plain radiographs and computed tomography scans were scored for bridging bone at multiple points during healing and at necropsy. The biomechanical competency of fusion was scored by manual palpation and quantified using functional radiographs at necropsy. Postnecropsy histopathology and histomorphometric analysis assessed the local response to MPC treatment and quantified the volume and connectivity of newly formed bridging bone. Safety was assessed by serum biochemistry, hematology, and organ histopathology. Mesenchymal precursor cell treatment caused no adverse systemic or local tissue responses. All analyses indicated MPCs combined with an osteoconductive scaffold achieved similar or better fusion success as AG treatment after 16 weeks, and increasing the MPC dose did not enhance fusion. Manual palpation of the fusion site indicated more than 75% of MPC-treated and 65% of AG-treated animals achieved rigid fusion, which was corroborated with functional radiography. Computed tomography fusion scores indicated all animals in the MPC- and AG-treatment groups were fused at 16 weeks, yet X-ray scores indicated only 67% of the AG-treated animals were fused. Histomorphometry analyses showed equivalent outcomes for fusion connectivity and bony fusion area for

Fusion Studies in Japan

NASA Astrophysics Data System (ADS)

Ogawa, Yuichi

2016-05-01

A new strategic energy plan decided by the Japanese Cabinet in 2014 strongly supports the steady promotion of nuclear fusion development activities, including the ITER project and the Broader Approach activities from the long-term viewpoint. Atomic Energy Commission (AEC) in Japan formulated the Third Phase Basic Program so as to promote an experimental fusion reactor project. In 2005 AEC has reviewed this Program, and discussed on selection and concentration among many projects of fusion reactor development. In addition to the promotion of ITER project, advanced tokamak research by JT-60SA, helical plasma experiment by LHD, FIREX project in laser fusion research and fusion engineering by IFMIF were highly prioritized. Although the basic concept is quite different between tokamak, helical and laser fusion researches, there exist a lot of common features such as plasma physics on 3-D magnetic geometry, high power heat load on plasma facing component and so on. Therefore, a synergetic scenario on fusion reactor development among various plasma confinement concepts would be important.

Fusion Rate and Clinical Outcomes in Two-Level Posterior Lumbar Interbody Fusion.

PubMed

Aono, Hiroyuki; Takenaka, Shota; Nagamoto, Yukitaka; Tobimatsu, Hidekazu; Yamashita, Tomoya; Furuya, Masayuki; Iwasaki, Motoki

2018-04-01

Posterior lumbar interbody fusion (PLIF) has become a general surgical method for degenerative lumbar diseases. Although many reports have focused on single-level PLIF, few have focused on 2-level PLIF, and no report has covered the fusion status of 2-level PLIF. The purpose of this study is to investigate clinical outcomes and fusion for 2-level PLIF by using a combination of dynamic radiographs and multiplanar-reconstruction computed tomography scans. This study consisted of 48 consecutive patients who underwent 2-level PLIF for degenerative lumbar diseases. We assessed surgery duration, estimated blood loss, complications, clinical outcomes as measured by the Japanese Orthopaedic Association score, lumbar sagittal alignment as measured on standing lateral radiographs, and fusion status as measured by dynamic radiographs and multiplanar-reconstruction computed tomography. Patients were examined at a follow-up point of 4.8 ± 2.2 years after surgery. Thirty-eight patients who did not undergo lumbosacral fusion comprised the lumbolumbar group, and 10 patients who underwent lumbosacral fusion comprised the lumbosacral group. The mean Japanese Orthopaedic Association score improved from 12.1 to 22.4 points by the final follow-up examination. Sagittal alignment also was improved. All patients had fusion in the cranial level. Seven patients had nonunion in the caudal level, and the lumbosacral group (40%) had a significantly poorer fusion rate than the lumbolumbar group (97%) did. Surgical outcomes of 2-level PLIF were satisfactory. The fusion rate at both levels was 85%. All nonunion was observed at the caudal level and concentrated at L5-S level in L4-5-S PLIF. Copyright © 2018 Elsevier Inc. All rights reserved.

Germline Defects Caused by Smed-boule RNA-Interference Reveal That Egg Capsule Deposition Occurs Independently of Fertilization, Ovulation, Mating, or the Presence of Gametes in Planarian Flatworms

PubMed Central

Steiner, Jessica Kathryne; Tasaki, Junichi; Rouhana, Labib

2016-01-01

Few animals are known to lay eggs in the absence of ovulation or copulation, as it is presumably energetically wasteful and subjected to negative selection. Characterization of Smed-boule, a member of the DAZ family of germline RNA-binding proteins, revealed that egg capsule (or capsule) production and deposition occurs independently of the presence of gametes in the planarian flatworm Schmidtea mediterranea. Reduction of Smed-boule expression by RNA-interference (RNAi) causes ablation of spermatogonial stem cells and the inability of ovarian germline stem cells to undergo oogenesis. Although animals subjected to Smed-boule RNAi lose their gametes and become sterile, they continue to lay egg capsules. Production of sterile capsules is even observed in virgin Smed-boule(RNAi) and control planarians maintained in complete isolation, demonstrating that egg production in S. mediterranea occurs independently of ovulation, fertilization, or mating. Evidence suggests that this is a conserved feature amongst Platyhelminthes, and therefore relevant to the pathology and dissemination of parasitic flatworms. These findings demonstrate that Smed-boule functions at different stages during male and female germline stem cell development, and also demonstrate that egg capsule production by planarian flatworms occurs independently of signals produced by mating or ova. PMID:27149082

Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy.

PubMed

Inoue, Hiroshi K; Nakajima, Atsushi; Sato, Hiro; Noda, Shin-Ei; Saitoh, Jun-Ichi; Suzuki, Yoshiyuki

2015-03-01

Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery. In vascular lesions, angiography is most important for evaluations of whole structures from feeder to drainer, shunt, blood flow and risk factors of bleeding. However, exact sites and surrounding structures in the brain are not shown on angiography. True image fusions of angiography, MR images and CT on axial planes are ideal for precise target definition. In malignant tumors, especially recurrent head and neck tumors, biologically active areas of recurrent tumors are main targets of radiosurgery. PET scan is useful for quantitative evaluation of recurrences. However, the examination is not always available at the time of radiosurgery. Image fusion of MR diffusion images with CT is always available during radiosurgery and useful for the detection of recurrent lesions. All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment. Follow-up images are also able to register on this CT. Exact target changes, including volume, are possible in this fusion system. The purpose of this review is to describe the usefulness of image fusion for 1) skull base, 2) vascular, 3) recurrent target detection, and 4) follow-up analyses in radiosurgery, neurosurgery and hypofractionated radiotherapy.

Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy

PubMed Central

Nakajima, Atsushi; Sato, Hiro; Noda, Shin-ei; Saitoh, Jun-ichi; Suzuki, Yoshiyuki

2015-01-01

Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery. In vascular lesions, angiography is most important for evaluations of whole structures from feeder to drainer, shunt, blood flow and risk factors of bleeding. However, exact sites and surrounding structures in the brain are not shown on angiography. True image fusions of angiography, MR images and CT on axial planes are ideal for precise target definition. In malignant tumors, especially recurrent head and neck tumors, biologically active areas of recurrent tumors are main targets of radiosurgery. PET scan is useful for quantitative evaluation of recurrences. However, the examination is not always available at the time of radiosurgery. Image fusion of MR diffusion images with CT is always available during radiosurgery and useful for the detection of recurrent lesions. All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment. Follow-up images are also able to register on this CT. Exact target changes, including volume, are possible in this fusion system. The purpose of this review is to describe the usefulness of image fusion for 1) skull base, 2) vascular, 3) recurrent target detection, and 4) follow-up analyses in radiosurgery, neurosurgery and hypofractionated radiotherapy. PMID:26180676

Simulation of polyethylene glycol and calcium-mediated membrane fusion

NASA Astrophysics Data System (ADS)

Pannuzzo, Martina; De Jong, Djurre H.; Raudino, Antonio; Marrink, Siewert J.

2014-03-01

We report on the mechanism of membrane fusion mediated by polyethylene glycol (PEG) and Ca2+ by means of a coarse-grained molecular dynamics simulation approach. Our data provide a detailed view on the role of cations and polymer in modulating the interaction between negatively charged apposed membranes. The PEG chains cause a reduction of the inter-lamellar distance and cause an increase in concentration of divalent cations. When thermally driven fluctuations bring the membranes at close contact, a switch from cis to trans Ca2+-lipid complexes stabilizes a focal contact acting as a nucleation site for further expansion of the adhesion region. Flipping of lipid tails induces subsequent stalk formation. Together, our results provide a molecular explanation for the synergistic effect of Ca2+ and PEG on membrane fusion.

Extraction of the Wichita Fusion Nail after Knee Arthrodesis

PubMed Central

Neuts, Ann-Sophie; Lammens, Johan; Stuyck, Jose

2016-01-01

To avoid a new exposition and partial damage of a knee arthrodesis site due to the removal of the Wichita fusion nail (WFN), a new extraction technique was developed, using a femoral osteotomy at the proximal end of the nail. Fixing the osteotomy with an Ilizarov frame offered the possibility to perform an additional correction of length and/or alignment if necessary. PMID:28529847

The Rab3A-22A Chimera Prevents Sperm Exocytosis by Stabilizing Open Fusion Pores*

PubMed Central

Quevedo, María F.; Lucchesi, Ornella; Bustos, Matías A.; Pocognoni, Cristian A.; De la Iglesia, Paola X.

2016-01-01

At the final stage of exocytotis, a fusion pore opens between the plasma and a secretory vesicle membranes; typically, when the pore dilates the vesicle releases its cargo. Sperm contain a large dense-core secretory granule (the acrosome) whose contents are secreted by regulated exocytosis at fertilization. Minutes after the arrival of the triggering signal, the acrosomal and plasma membranes dock at multiple sites and fusion pores open at the contact points. It is believed that immediately afterward, fusion pores dilate spontaneously. Rab3A is an essential component of human sperm exocytotic machinery. Yet, recombinant, persistently active Rab3A halts calcium-triggered secretion when introduced after docking into streptolysin O-permeabilized cells; so does a Rab3A-22A chimera. Here, we applied functional assays, electron and confocal microscopy to show that the secretion blockage is due to the stabilization of open fusion pores. Other novel findings are that sperm SNAREs engage in α-SNAP/NSF-sensitive complexes at a post-fusion stage. Complexes are disentangled by these chaperons to achieve vesiculation and acrosomal contents release. Thus, post-fusion regulation of the pores determines their expansion and the success of the acrosome reaction. PMID:27613869

Hydrogen isotopes transport parameters in fusion reactor materials

NASA Astrophysics Data System (ADS)

Serra, E.; Benamati, G.; Ogorodnikova, O. V.

1998-06-01

This work presents a review of hydrogen isotopes-materials interactions in various materials of interest for fusion reactors. The relevant parameters cover mainly diffusivity, solubility, trap concentration and energy difference between trap and solution sites. The list of materials includes the martensitic steels (MANET, Batman and F82H-mod.), beryllium, aluminium, beryllium oxide, aluminium oxide, copper, tungsten and molybdenum. Some experimental work on the parameters that describe the surface effects is also mentioned.

Control of mechanically activated polymersome fusion: Factors affecting fusion

DOE PAGES

Henderson, Ian M.; Paxton, Walter F.

2014-12-15

Previously we have studied the mechanically-activated fusion of extruded (200 nm) polymer vesicles into giant polymersomes using agitation in the presence of salt. In this study we have investigated several factors contributing to this phenomenon, including the effects of (i) polymer vesicle concentration, (ii) agitation speed and duration, and iii) variation of the salt and its concentration. It was found that increasing the concentration of the polymer dramatically increases the production of giant vesicles through the increased collisions of polymersomes. Our investigations also found that increasing the frequency of agitation increased the efficiency of fusion, though ultimately limited the sizemore » of vesicle which could be produced due to the high shear involved. Finally it was determined that salt-mediation of the fusion process was not limited to NaCl, but is instead a general effect facilitated by the presence of solvated ionic compounds, albeit with different salts initiating fusion at different concentration.« less

Image fusion

NASA Technical Reports Server (NTRS)

Pavel, M.

1993-01-01

The topics covered include the following: a system overview of the basic components of a system designed to improve the ability of a pilot to fly through low-visibility conditions such as fog; the role of visual sciences; fusion issues; sensor characterization; sources of information; image processing; and image fusion.

50 years of fusion research

NASA Astrophysics Data System (ADS)

Meade, Dale

2010-01-01

Fusion energy research began in the early 1950s as scientists worked to harness the awesome power of the atom for peaceful purposes. There was early optimism for a quick solution for fusion energy as there had been for fission. However, this was soon tempered by reality as the difficulty of producing and confining fusion fuel at temperatures of 100 million °C in the laboratory was appreciated. Fusion research has followed two main paths—inertial confinement fusion and magnetic confinement fusion. Over the past 50 years, there has been remarkable progress with both approaches, and now each has a solid technical foundation that has led to the construction of major facilities that are aimed at demonstrating fusion energy producing plasmas.

Radiation and Electromagnetic Induction Data Fusion for Detection of Buried Radioactive Metal Waste - 12282

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Zhiling; Wei, Wei; Turlapaty, Anish

2012-07-01

At the United States Army's test sites, fired penetrators made of Depleted Uranium (DU) have been buried under ground and become hazardous waste. Previously, we developed techniques for detecting buried radioactive targets. We also developed approaches for locating buried paramagnetic metal objects by utilizing the electromagnetic induction (EMI) sensor data. In this paper, we apply data fusion techniques to combine results from both the radiation detection and the EMI detection, so that we can further distinguish among DU penetrators, DU oxide, and non- DU metal debris. We develop a two-step fusion approach for the task, and test it with surveymore » data collected on simulation targets. In this work, we explored radiation and EMI data fusion for detecting DU, oxides, and non-DU metals. We developed a two-step fusion approach based on majority voting and a set of decision rules. With this approach, we fuse results from radiation detection based on the RX algorithm and EMI detection based on a 3-step analysis. Our fusion approach has been tested successfully with data collected on simulation targets. In the future, we will need to further verify the effectiveness of this fusion approach with field data. (authors)« less

Identification of Novel Fusion Inhibitors of Influenza A Virus by Chemical Genetics

PubMed Central

Lai, Kin Kui; Cheung, Nam Nam; Yang, Fang; Dai, Jun; Liu, Li; Chen, Zhiwei; Sze, Kong Hung; Chen, Honglin

2015-01-01

ABSTRACT A previous screening of more than 50,000 compounds led to the identification of a pool of bioactive small molecules with inhibitory effect on the influenza A virus. One of these compounds, now widely known as nucleozin, is a small molecule that targets the influenza A virus nucleoprotein. Here we identify and characterize two structurally different novel fusion inhibitors of the influenza A virus group 1 hemagglutinin (HA), FA-583 and FA-617, with low nanomolar activities. Escape mutants that are highly resistant to each of these compounds were generated, and both were found to carry mutations localized in close proximity to the B-loop of the hemagglutinin 2 protein, which plays a crucial role in the virion-host cell fusion process. Recombinant virus, generated through reverse genetics, confirmed the resistance phenotype. In addition, the proposed binding pockets predicted by molecular docking studies are in accordance with the resistance-bearing mutation sites. We show through mechanistic studies that FA-583 and FA-617 act as fusion inhibitors by prohibiting the low-pH-induced conformational change of hemagglutinin. Our study has offered concrete biological and mechanistic explorations for the strategic development of novel fusion inhibitors of influenza A viruses. IMPORTANCE Here we report two structurally distinctive novel fusion inhibitors of influenza A virus that act by interfering with the structural change of HA at acidic pH, a process necessary for successful entry of the virus. Mutational and molecular docking studies have identified their binding pockets situated in close proximity to the B-loop region of hemagglutinin 2. The reduced sensitivity of FA-583- or FA-617-associated mutants to another compound suggests a close proximity and even partial overlap of their binding sites on hemagglutinin. Amino acid sequence alignments and crystal structure analyses of group 1 and group 2 hemagglutinins have shed light on the possible binding mode of

The Habc Domain of the SNARE Vam3 Interacts with the HOPS Tethering Complex to Facilitate Vacuole Fusion*

PubMed Central

Lürick, Anna; Kuhlee, Anne; Bröcker, Cornelia; Kümmel, Daniel; Raunser, Stefan; Ungermann, Christian

2015-01-01

Membrane fusion at vacuoles requires a consecutive action of the HOPS tethering complex, which is recruited by the Rab GTPase Ypt7, and vacuolar SNAREs to drive membrane fusion. It is assumed that the Sec1/Munc18-like Vps33 within the HOPS complex is largely responsible for SNARE chaperoning. Here, we present direct evidence for HOPS binding to SNAREs and the Habc domain of the Vam3 SNARE protein, which may explain its function during fusion. We show that HOPS interacts strongly with the Vam3 Habc domain, assembled Q-SNAREs, and the R-SNARE Ykt6, but not the Q-SNARE Vti1 or the Vam3 SNARE domain. Electron microscopy combined with Nanogold labeling reveals that the binding sites for vacuolar SNAREs and the Habc domain are located in the large head of the HOPS complex, where Vps16 and Vps33 have been identified before. Competition experiments suggest that HOPS bound to the Habc domain can still interact with assembled Q-SNAREs, whereas Q-SNARE binding prevents recognition of the Habc domain. In agreement, membranes carrying Vam3ΔHabc fuse poorly unless an excess of HOPS is provided. These data suggest that the Habc domain of Vam3 facilitates the assembly of the HOPS/SNARE machinery at fusion sites and thus supports efficient membrane fusion. PMID:25564619

Fusion for Space Propulsion

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

2001-01-01

There is little doubt that humans will attempt to explore and develop the solar system in this century. A large amount of energy will be required for accomplishing this. The need for fusion propulsion is discussed. For a propulsion system, there are three important thermodynamical attributes: (1) The absolute amount of energy available, (2) the propellant exhaust velocity, and (3) the jet power per unit mass of the propulsion system (specific power). For human exploration and development of the solar system, propellant exhaust velocity in excess of 100 km/s and specific power in excess of 10 kW/kg are required. Chemical combustion can produce exhaust velocity up to about 5 km/s. Nuclear fission processes typically result in producing energy in the form of heat that needs to be manipulated at temperatures limited by materials to about 2,800 K. Using the energy to heat a hydrogen propellant increases the exhaust velocity by only a factor of about two. Alternatively the energy can be converted into electricity which is then used to accelerate particles to high exhaust velocity. The necessary power conversion and conditioning equipment, however, increases the mass of the propulsion system for the same jet power by more than two orders of magnitude over chemical system, thus greatly limits the thrust-to-weight ratio attainable. The principal advantage of the fission process is that its development is relatively mature and is available right now. If fusion can be developed, fusion appears to have the best of all worlds in terms of propulsion - it can provide the absolute amount, the propellant exhaust velocity, and the high specific jet power. An intermediate step towards pure fusion propulsion is a bimodal system in which a fission reactor is used to provide some of the energy to drive a fusion propulsion unit. The technical issues related to fusion for space propulsion are discussed. The technical priorities for developing and applying fusion for propulsion are

C-terminal tyrosine residues modulate the fusion activity of the Hendra virus fusion protein

PubMed Central

Popa, Andreea; Pager, Cara Teresia; Dutch, Rebecca Ellis

2011-01-01

The paramyxovirus family includes important human pathogens such as measles, mumps, respiratory syncytial virus and the recently emerged, highly pathogenic Hendra and Nipah viruses. The viral fusion (F) protein plays critical roles in infection, promoting both the viral-cell membrane fusion events needed for viral entry as well as cell-cell fusion events leading to syncytia formation. We describe the surprising finding that addition of the short epitope HA tag to the cytoplasmic tail (CT) of the Hendra virus F protein leads to a significant increase in cell-cell membrane fusion. This increase was not due to alterations in surface expression, cleavage state, or association with lipid microdomains. Addition of a Myc tag of similar length did not alter Hendra F fusion activity, indicating that the observed stimulation was not solely a result of lengthening the CT. Three tyrosine residues within the HA tag were critical for the increase in fusion, suggesting C-terminal tyrosines may modulate Hendra fusion activity. The effects of HA tag addition varied with other fusion proteins, as parainfluenza virus 5 F-HA showed decreased surface expression and no stimulation in fusion. These results indicate that additions to the C-terminal end of the F protein CT can modulate protein function in a sequence specific manner, reinforcing the need for careful analysis of epitope tagged glycoproteins. In addition, our results implicate C-terminal tyrosine residues in modulation of the membrane fusion reaction promoted by these viral glycoproteins. PMID:21175223

Opioids delay healing of spinal fusion: a rabbit posterolateral lumbar fusion model.

PubMed

Jain, Nikhil; Himed, Khaled; Toth, Jeffrey M; Briley, Karen C; Phillips, Frank M; Khan, Safdar N

2018-04-19

Opioid use is prevalent for management of pre- and post-operative pain in patients undergoing spinal fusion. There is evidence that opioids downregulate osteoblasts in-vitro, and one previous study found that morphine delays the maturation and remodeling of callus in a rat femur fracture model. However, the effect of opioids on healing of spinal fusion has not been investigated before. Isolating the effect of opioid exposure in humans would be limited by the numerous confounding factors that affect fusion healing. Therefore, we have used a well-established rabbit model to study the process of spinal fusion healing that closely mimics humans. To study the effect of systemic opioids on the process of healing of spinal fusion in a rabbit posterolateral spinal fusion model. Pre-clinical animal study. 24 adult New Zealand white rabbits were studied in two groups after approval from the Institutional Animal Care and Use Committee (IACUC). The opioid group (n=12) received four-weeks pre-operative and six-weeks post-operative transdermal fentanyl. Serum fentanyl levels were measured just before surgery and four-weeks post-operatively to ensure adequate levels. The control group (n=12) received only peri-operative pain control as necessary. All animals received a bilateral L5-L6 posterolateral spinal fusion using iliac crest autograft. Animals were euthanized at the six-week post-operative time point, and assessment of fusion was done by manual palpation, plain radiographs, micro-computed tomography (microCT), and histology. 12 animals in control group and 11 animals in the opioid group were available for analysis at the end of six weeks. The fusion scores on manual palpation, radiographs, and microCT were not statistically different. Three-dimensional microCT morphometry found that the fusion mass in the opioid group had a lower bone volume (p=0.09), lower trabecular number (p=0.02) and higher trabecular separation (p=0.02) as compared to control. Histological analysis

Structure of the cleavage-activated prefusion form of the parainfluenza virus 5 fusion protein.

PubMed

Welch, Brett D; Liu, Yuanyuan; Kors, Christopher A; Leser, George P; Jardetzky, Theodore S; Lamb, Robert A

2012-10-09

The paramyxovirus parainfluenza virus 5 (PIV5) enters cells by fusion of the viral envelope with the plasma membrane through the concerted action of the fusion (F) protein and the receptor binding protein hemagglutinin-neuraminidase. The F protein folds initially to form a trimeric metastable prefusion form that is triggered to undergo large-scale irreversible conformational changes to form the trimeric postfusion conformation. It is thought that F refolding couples the energy released with membrane fusion. The F protein is synthesized as a precursor (F0) that must be cleaved by a host protease to form a biologically active molecule, F1,F2. Cleavage of F protein is a prerequisite for fusion and virus infectivity. Cleavage creates a new N terminus on F1 that contains a hydrophobic region, known as the FP, which intercalates target membranes during F protein refolding. The crystal structure of the soluble ectodomain of the uncleaved form of PIV5 F is known; here we report the crystal structure of the cleavage-activated prefusion form of PIV5 F. The structure shows minimal movement of the residues adjacent to the protease cleavage site. Most of the hydrophobic FP residues are buried in the uncleaved F protein, and only F103 at the newly created N terminus becomes more solvent-accessible after cleavage. The conformational freedom of the charged arginine residues that compose the protease recognition site increases on cleavage of F protein.

Structure of the cleavage-activated prefusion form of the parainfluenza virus 5 fusion protein

PubMed Central

Welch, Brett D.; Liu, Yuanyuan; Kors, Christopher A.; Leser, George P.; Jardetzky, Theodore S.; Lamb, Robert A.

2012-01-01

The paramyxovirus parainfluenza virus 5 (PIV5) enters cells by fusion of the viral envelope with the plasma membrane through the concerted action of the fusion (F) protein and the receptor binding protein hemagglutinin-neuraminidase. The F protein folds initially to form a trimeric metastable prefusion form that is triggered to undergo large-scale irreversible conformational changes to form the trimeric postfusion conformation. It is thought that F refolding couples the energy released with membrane fusion. The F protein is synthesized as a precursor (F0) that must be cleaved by a host protease to form a biologically active molecule, F1,F2. Cleavage of F protein is a prerequisite for fusion and virus infectivity. Cleavage creates a new N terminus on F1 that contains a hydrophobic region, known as the FP, which intercalates target membranes during F protein refolding. The crystal structure of the soluble ectodomain of the uncleaved form of PIV5 F is known; here we report the crystal structure of the cleavage-activated prefusion form of PIV5 F. The structure shows minimal movement of the residues adjacent to the protease cleavage site. Most of the hydrophobic FP residues are buried in the uncleaved F protein, and only F103 at the newly created N terminus becomes more solvent-accessible after cleavage. The conformational freedom of the charged arginine residues that compose the protease recognition site increases on cleavage of F protein. PMID:23012473

Individual N-Glycans Added at Intervals along the Stalk of the Nipah Virus G Protein Prevent Fusion but Do Not Block the Interaction with the Homologous F Protein

PubMed Central

Zhu, Qiyun; Biering, Scott B.; Mirza, Anne M.; Grasseschi, Brittany A.; Mahon, Paul J.; Lee, Benhur; Aguilar, Hector C.

2013-01-01

The promotion of membrane fusion by most paramyxoviruses requires an interaction between the viral attachment and fusion (F) proteins to enable receptor binding by the former to trigger the activation of the latter for fusion. Numerous studies demonstrate that the F-interactive sites on the Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) and measles virus (MV) hemagglutinin (H) proteins reside entirely within the stalk regions of those proteins. Indeed, stalk residues of NDV HN and MV H that likely mediate the F interaction have been identified. However, despite extensive efforts, the F-interactive site(s) on the Nipah virus (NiV) G attachment glycoprotein has not been identified. In this study, we have introduced individual N-linked glycosylation sites at several positions spaced at intervals along the stalk of the NiV G protein. Five of the seven introduced sites are utilized as established by a retardation of electrophoretic mobility. Despite surface expression, ephrinB2 binding, and oligomerization comparable to those of the wild-type protein, four of the five added N-glycans completely eliminate the ability of the G protein to complement the homologous F protein in the promotion of fusion. The most membrane-proximal added N-glycan reduces fusion by 80%. However, unlike similar NDV HN and MV H mutants, the NiV G glycosylation stalk mutants retain the ability to bind F, indicating that the fusion deficiency of these mutants is not due to prevention of the G-F interaction. These findings suggest that the G-F interaction is not mediated entirely by the stalk domain of G and may be more complex than that of HN/H-F. PMID:23283956

Inducible model for β-six-mediated site-specific recombination in mammalian cells

PubMed Central

Servert, Pilar; Garcia-Castro, Javier; Díaz, Vicente; Lucas, Daniel; Gonzalez, Manuel A.; Martínez-A, Carlos; Bernad, Antonio

2006-01-01

The prokaryotic β recombinase catalyzes site-specific recombination between two directly oriented minimal six sites in chromatin-integrated substrates. Here, we demonstrate that an enhanced green fluorescent protein (EGFP)-fused version of β recombinase (β-EGFP) is fully active, retaining most specific activity. It is used to develop a recombination-dependent activatable gene expression (RAGE) system based on the androgen receptor (AR) ligand-binding domain (LBD). Two hybrid molecules, a direct fusion of the LBD-AR to the C-terminus of β recombinase (β-AR) and a triple fusion of β-EGFP to the same ligand-binding domain (β-EGFP-AR), were engineered and their subcellular behavior, stability and catalytic activity were evaluated. Both chimeric β recombinase proteins showed in vivo inducible recombinogenic activity dependent on addition of an androgen receptor agonist, although the β-AR fusion protein demonstrated more accurate ligand-dependent translocation from cytoplasm to nucleus. PMID:16394020

Systematic analysis of advanced fusion fuel in inertial fusion energy

NASA Astrophysics Data System (ADS)

Velarde, G.; Eliezer, S.; Henis, Z.; Piera, M.; Martinez-Val, J. M.

1997-04-01

Aneutronic fusion reactions can be considered as the cleanest way to exploit nuclear energy. However, these reactions present in general two main drawbacks.—very high temperatures are needed to reach relevant values of their cross sections—Moderate (and even low) energy yield per reaction. This value is still lower if measured in relation to the Z number of the reacting particles. It is already known that bremsstrahlung overruns the plasma reheating by fusion born charged-particles in most of the advanced fuels. This is for instance the case for proton-boron-11 fusion in a stoichiometric plasma and is also so in lithium isotopes fusion reactions. In this paper, the use of deuterium-tritium seeding is suggested to allow to reach higher burnup fractions of advanced fuels, starting at a lower ignition temperature. Of course, neutron production increases as DT contents does. Nevertheless, the ratio of neutron production to energy generation is much lower in DT-advanced fuel mixtures than in pure DT plasmas. One of the main findings of this work is that some natural resources (as D and Li-7) can be burned-up in a catalytic regime for tritium. In this case, neither external tritium breeding nor tritium storage are needed, because the tritium inventory after the fusion burst is the same as before it. The fusion reactor can thus operate on a pure recycling of a small tritium inventory.

FusionHub: A unified web platform for annotation and visualization of gene fusion events in human cancer.

PubMed

Panigrahi, Priyabrata; Jere, Abhay; Anamika, Krishanpal

2018-01-01

Gene fusion is a chromosomal rearrangement event which plays a significant role in cancer due to the oncogenic potential of the chimeric protein generated through fusions. At present many databases are available in public domain which provides detailed information about known gene fusion events and their functional role. Existing gene fusion detection tools, based on analysis of transcriptomics data usually report a large number of fusion genes as potential candidates, which could be either known or novel or false positives. Manual annotation of these putative genes is indeed time-consuming. We have developed a web platform FusionHub, which acts as integrated search engine interfacing various fusion gene databases and simplifies large scale annotation of fusion genes in a seamless way. In addition, FusionHub provides three ways of visualizing fusion events: circular view, domain architecture view and network view. Design of potential siRNA molecules through ensemble method is another utility integrated in FusionHub that could aid in siRNA-based targeted therapy. FusionHub is freely available at https://fusionhub.persistent.co.in.

Gene Fusion Markup Language: a prototype for exchanging gene fusion data.

PubMed

Kalyana-Sundaram, Shanker; Shanmugam, Achiraman; Chinnaiyan, Arul M

2012-10-16

An avalanche of next generation sequencing (NGS) studies has generated an unprecedented amount of genomic structural variation data. These studies have also identified many novel gene fusion candidates with more detailed resolution than previously achieved. However, in the excitement and necessity of publishing the observations from this recently developed cutting-edge technology, no community standardization approach has arisen to organize and represent the data with the essential attributes in an interchangeable manner. As transcriptome studies have been widely used for gene fusion discoveries, the current non-standard mode of data representation could potentially impede data accessibility, critical analyses, and further discoveries in the near future. Here we propose a prototype, Gene Fusion Markup Language (GFML) as an initiative to provide a standard format for organizing and representing the significant features of gene fusion data. GFML will offer the advantage of representing the data in a machine-readable format to enable data exchange, automated analysis interpretation, and independent verification. As this database-independent exchange initiative evolves it will further facilitate the formation of related databases, repositories, and analysis tools. The GFML prototype is made available at http://code.google.com/p/gfml-prototype/. The Gene Fusion Markup Language (GFML) presented here could facilitate the development of a standard format for organizing, integrating and representing the significant features of gene fusion data in an inter-operable and query-able fashion that will enable biologically intuitive access to gene fusion findings and expedite functional characterization. A similar model is envisaged for other NGS data analyses.

Gene Fusion Markup Language: a prototype for exchanging gene fusion data

PubMed Central

2012-01-01

Background An avalanche of next generation sequencing (NGS) studies has generated an unprecedented amount of genomic structural variation data. These studies have also identified many novel gene fusion candidates with more detailed resolution than previously achieved. However, in the excitement and necessity of publishing the observations from this recently developed cutting-edge technology, no community standardization approach has arisen to organize and represent the data with the essential attributes in an interchangeable manner. As transcriptome studies have been widely used for gene fusion discoveries, the current non-standard mode of data representation could potentially impede data accessibility, critical analyses, and further discoveries in the near future. Results Here we propose a prototype, Gene Fusion Markup Language (GFML) as an initiative to provide a standard format for organizing and representing the significant features of gene fusion data. GFML will offer the advantage of representing the data in a machine-readable format to enable data exchange, automated analysis interpretation, and independent verification. As this database-independent exchange initiative evolves it will further facilitate the formation of related databases, repositories, and analysis tools. The GFML prototype is made available at http://code.google.com/p/gfml-prototype/. Conclusion The Gene Fusion Markup Language (GFML) presented here could facilitate the development of a standard format for organizing, integrating and representing the significant features of gene fusion data in an inter-operable and query-able fashion that will enable biologically intuitive access to gene fusion findings and expedite functional characterization. A similar model is envisaged for other NGS data analyses. PMID:23072312

Gradient-based multiresolution image fusion.

PubMed

Petrović, Valdimir S; Xydeas, Costas S

2004-02-01

A novel approach to multiresolution signal-level image fusion is presented for accurately transferring visual information from any number of input image signals, into a single fused image without loss of information or the introduction of distortion. The proposed system uses a "fuse-then-decompose" technique realized through a novel, fusion/decomposition system architecture. In particular, information fusion is performed on a multiresolution gradient map representation domain of image signal information. At each resolution, input images are represented as gradient maps and combined to produce new, fused gradient maps. Fused gradient map signals are processed, using gradient filters derived from high-pass quadrature mirror filters to yield a fused multiresolution pyramid representation. The fused output image is obtained by applying, on the fused pyramid, a reconstruction process that is analogous to that of conventional discrete wavelet transform. This new gradient fusion significantly reduces the amount of distortion artefacts and the loss of contrast information usually observed in fused images obtained from conventional multiresolution fusion schemes. This is because fusion in the gradient map domain significantly improves the reliability of the feature selection and information fusion processes. Fusion performance is evaluated through informal visual inspection and subjective psychometric preference tests, as well as objective fusion performance measurements. Results clearly demonstrate the superiority of this new approach when compared to conventional fusion systems.

A Cell-Cell Fusion Assay to Assess Arenavirus Envelope Glycoprotein Membrane-Fusion Activity.

PubMed

York, Joanne; Nunberg, Jack H

2018-01-01

For many viruses that enter their target cells through pH-dependent fusion of the viral and endosomal membranes, cell-cell fusion assays can provide an experimental platform for investigating the structure-function relationships that promote envelope glycoprotein membrane-fusion activity. Typically, these assays employ effector cells expressing the recombinant envelope glycoprotein on the cell surface and target cells engineered to quantitatively report fusion with the effector cell. In the protocol described here, Vero cells are transfected with a plasmid encoding the arenavirus envelope glycoprotein complex GPC and infected with the vTF7-3 vaccinia virus expressing the bacteriophage T7 RNA polymerase. These effector cells are mixed with target cells infected with the vCB21R-lacZ vaccinia virus encoding a β-galactosidase reporter under the control of the T7 promoter. Cell-cell fusion is induced upon exposure to low-pH medium (pH 5.0), and the resultant expression of the β-galactosidase reporter is quantitated using a chemiluminescent substrate. We have utilized this robust microplate cell-cell fusion assay extensively to study arenavirus entry and its inhibition by small-molecule fusion inhibitors.

ITER Fusion Energy

ScienceCinema

Holtkamp, Norbert

2018-01-09

ITER (in Latin “the way”) is designed to demonstrate the scientific and technological feasibility of fusion energy. Fusion is the process by which two light atomic nuclei combine to form a heavier over one and thus release energy. In the fusion process two isotopes of hydrogen – deuterium and tritium – fuse together to form a helium atom and a neutron. Thus fusion could provide large scale energy production without greenhouse effects; essentially limitless fuel would be available all over the world. The principal goals of ITER are to generate 500 megawatts of fusion power for periods of 300 to 500 seconds with a fusion power multiplication factor, Q, of at least 10. Q ? 10 (input power 50 MW / output power 500 MW). The ITER Organization was officially established in Cadarache, France, on 24 October 2007. The seven members engaged in the project – China, the European Union, India, Japan, Korea, Russia and the United States – represent more than half the world’s population. The costs for ITER are shared by the seven members. The cost for the construction will be approximately 5.5 billion Euros, a similar amount is foreseen for the twenty-year phase of operation and the subsequent decommissioning.

Membrane topology analysis of Escherichia coli K-12 Mtr permease by alkaline phosphatase and beta-galactosidase fusions.

PubMed

Sarsero, J P; Pittard, A J

1995-01-01

The mtr gene of Escherichia coli K-12 encodes an inner membrane protein which is responsible for the active transport of trypotophan into the cell. It has been proposed that the Mtr permease has a novel structure consisting of 11 hydrophobic transmembrane spans, with a cytoplasmically disposed amino terminus and a carboxyl terminus located in the periplasmic space (J.P. Sarsero, P. J. Wookey, P. Gollnick, C. Yanofsky, and A.J. Pittard, J. Bacteriol. 173:3231-3234, 1991). The validity of this model was examined by the construction of fusion proteins between the Mtr permease and alkaline phosphatase or beta-galactosidase. In addition to the conventional methods, in which the reporter enzyme replaces a carboxyl-terminal portion of the membrane protein, the recently developed alkaline phosphatase sandwich fusion technique was utilized, in which alkaline phosphatase is inserted into an otherwise intact membrane protein. A cluster of alkaline phosphatase fusions to the carboxyl-terminal end of the Mtr permease exhibited high levels of alkaline phosphatase activity, giving support to the proposition of a periplasmically located carboxyl terminus. The majority of fusion proteins produced enzymatic activities which were in agreement with the positions of the fusion sites on the proposed topological model of the permease. The synthesis of a small cluster of hybrid proteins, whose enzymatic activity did not agree with the location of their fusion sites within putative transmembrane span VIII or the preceding periplasmic loop, was not detected by immunological techniques and did not necessitate modification of the proposed model in this region. Slight alterations may need to be made in the positioning of the carboxyl-terminal end of transmembrane span X.

Combined NMR and EPR Spectroscopy to Determine Structures of Viral Fusion Domains in Membranes

PubMed Central

Tamm, Lukas K.; Lai, Alex L.; Li, Yinling

2008-01-01

Methods are described to determine the structures of viral membrane fusion domains in detergent micelles by NMR and in lipid bilayers by site-directed spin labeling and EPR spectroscopy. Since in favorable cases, the lower-resolution spin label data obtained in lipid bilayers fully support the higher-resolution structures obtained by solution NMR, it is possible to graft the NMR structural coordinates into membranes using the EPR-derived distance restraints to the lipid bilayer. Electron paramagnetic dynamics and distance measurements in bilayers support conclusions drawn from NMR in detergent micelles. When these methods are applied to a structure determination of the influenza virus fusion domain and four point mutations with different functional phenotypes, it is evident that a fixed-angle boomerang structure with a glycine edge on the outside of the N-terminal arm is both necessary and sufficient to support membrane fusion. The human immunodeficiency virus fusion domain forms a straight helix with a flexible C-terminus. While EPR data for this fusion domain are not yet available, it is tentatively speculated that, because of its higher hydrophobicity, a critically tilted insertion may occur even in the absence of a kinked boomerang structure in this case. PMID:17963720

Targeted expression, purification, and cleavage of fusion proteins from inclusion bodies in Escherichia coli.

PubMed

Hwang, Peter M; Pan, Jonathan S; Sykes, Brian D

2014-01-21

Today, proteins are typically overexpressed using solubility-enhancing fusion tags that allow for affinity chromatographic purification and subsequent removal by site-specific protease cleavage. In this review, we present an alternative approach to protein production using fusion partners specifically designed to accumulate in insoluble inclusion bodies. The strategy is appropriate for the mass production of short peptides, intrinsically disordered proteins, and proteins that can be efficiently refolded in vitro. There are many fusion protein systems now available for insoluble expression: TrpLE, ketosteroid isomerase, PurF, and PagP, for example. The ideal fusion partner is effective at directing a wide variety of target proteins into inclusion bodies, accumulates in large quantities in a highly pure form, and is readily solubilized and purified in commonly used denaturants. Fusion partner removal under denaturing conditions is biochemically challenging, requiring harsh conditions (e.g., cyanogen bromide in 70% formic acid) that can result in unwanted protein modifications. Recent advances in metal ion-catalyzed peptide bond cleavage allow for more mild conditions, and some methods involving nickel or palladium will likely soon appear in more biological applications. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Paramyxovirus F1 protein has two fusion peptides: implications for the mechanism of membrane fusion.

PubMed

Peisajovich, S G; Samuel, O; Shai, Y

2000-03-10

Viral fusion proteins contain a highly hydrophobic segment, named the fusion peptide, which is thought to be responsible for the merging of the cellular and viral membranes. Paramyxoviruses are believed to contain a single fusion peptide at the N terminus of the F1 protein. However, here we identified an additional internal segment in the Sendai virus F1 protein (amino acids 214-226) highly homologous to the fusion peptides of HIV-1 and RSV. A synthetic peptide, which includes this region, was found to induce membrane fusion of large unilamellar vesicles, at concentrations where the known N-terminal fusion peptide is not effective. A scrambled peptide as well as several peptides from other regions of the F1 protein, which strongly bind to membranes, are not fusogenic. The functional and structural characterization of this active segment suggest that the F1 protein has an additional internal fusion peptide that could participate in the actual fusion event. The presence of homologous regions in other members of the same family suggests that the concerted action of two fusion peptides, one N-terminal and the other internal, is a general feature of paramyxoviruses. Copyright 2000 Academic Press.

Mutagenesis of the La Crosse Virus glycoprotein supports a role for Gc (1066-1087) as the fusion peptide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plassmeyer, Matthew L.; Graduate Group Molecular and Cell Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6058; Soldan, Samantha S.

The La Crosse Virus (LACV) M segment encodes two glycoproteins (Gn and Gc), and plays a critical role in the neuropathogenesis of LACV infection as the primary determinant of neuroinvasion. A recent study from our group demonstrated that the region comprising the membrane proximal two-thirds of Gc, amino acids 860-1442, is critical in mediating LACV fusion and entry. Furthermore, computational analysis identified structural similarities between a portion of this region, amino acids 970-1350, and the E1 fusion protein of two alphaviruses: Sindbis virus and Semliki Forrest virus (SFV). Within the region 970-1350, a 22-amino-acid hydrophobic segment (1066-1087) is predicted tomore » correlate structurally with the fusion peptides of class II fusion proteins. We performed site-directed mutagenesis of key amino acids in this 22-amino acid segment and determined the functional consequences of these mutations on fusion and entry. Several mutations within this hydrophobic domain affected glycoprotein expression to some extent, but all mutations either shifted the pH threshold of fusion below that of the wild-type protein, reduced fusion efficiency, or abrogated cell-to-cell fusion and pseudotype entry altogether. These results, coupled with the aforementioned computational modeling, suggest that the LACV Gc functions as a class II fusion protein and support a role for the region Gc 1066-1087 as a fusion peptide.« less

Investigations of image fusion

NASA Astrophysics Data System (ADS)

Zhang, Zhong

1999-12-01

The objective of image fusion is to combine information from multiple images of the same scene. The result of image fusion is a single image which is more suitable for the purpose of human visual perception or further image processing tasks. In this thesis, a region-based fusion algorithm using the wavelet transform is proposed. The identification of important features in each image, such as edges and regions of interest, are used to guide the fusion process. The idea of multiscale grouping is also introduced and a generic image fusion framework based on multiscale decomposition is studied. The framework includes all of the existing multiscale-decomposition- based fusion approaches we found in the literature which did not assume a statistical model for the source images. Comparisons indicate that our framework includes some new approaches which outperform the existing approaches for the cases we consider. Registration must precede our fusion algorithms. So we proposed a hybrid scheme which uses both feature-based and intensity-based methods. The idea of robust estimation of optical flow from time- varying images is employed with a coarse-to-fine multi- resolution approach and feature-based registration to overcome some of the limitations of the intensity-based schemes. Experiments show that this approach is robust and efficient. Assessing image fusion performance in a real application is a complicated issue. In this dissertation, a mixture probability density function model is used in conjunction with the Expectation- Maximization algorithm to model histograms of edge intensity. Some new techniques are proposed for estimating the quality of a noisy image of a natural scene. Such quality measures can be used to guide the fusion. Finally, we study fusion of images obtained from several copies of a new type of camera developed for video surveillance. Our techniques increase the capability and reliability of the surveillance system and provide an easy way to obtain 3-D

EDITORIAL: Safety aspects of fusion power plants

NASA Astrophysics Data System (ADS)

Kolbasov, B. N.

2007-07-01

importance for the fusion power plant research programmes. The objective of this Technical Meeting was to examine in an integrated way all the safety aspects anticipated to be relevant to the first fusion power plant prototype expected to become operational by the middle of the century, leading to the first generation of economically viable fusion power plants with attractive S&E features. After screening by guest editors and consideration by referees, 13 (out of 28) papers were accepted for publication. They are devoted to the following safety topics: power plant safety; fusion specific operational safety approaches; test blanket modules; accident analysis; tritium safety and inventories; decommissioning and waste. The paper `Main safety issues at the transition from ITER to fusion power plants' by W. Gulden et al (EU) highlights the differences between ITER and future fusion power plants with magnetic confinement (off-site dose acceptance criteria, consequences of accidents inside and outside the design basis, occupational radiation exposure, and waste management, including recycling and/or final disposal in repositories) on the basis of the most recent European fusion power plant conceptual study. Ongoing S&E studies within the US inertial fusion energy (IFE) community are focusing on two design concepts. These are the high average power laser (HAPL) programme for development of a dry-wall, laser-driven IFE power plant, and the Z-pinch IFE programme for the production of an economically-attractive power plant using high-yield Z-pinch-driven targets. The main safety issues related to these programmes are reviewed in the paper `Status of IFE safety and environmental activities in the US' by S. Reyes et al (USA). The authors propose future directions of research in the IFE S&E area. In the paper `Recent accomplishments and future directions in the US Fusion Safety & Environmental Program' D. Petti et al (USA) state that the US fusion programme has long recognized that the S

The limits of evidence: evidence based policy and the removal of gamete donor anonymity in the UK.

PubMed

Frith, Lucy

2015-03-01

This paper will critically examine the use of evidence in creating policy in the area of reproductive technologies. The use of evidence in health care and policy is not a new phenomenon. However, codified strategies for evidence appraisal in health care technology assessments and attempts to create evidence based policy initiatives suggest that the way evidence is used in practice and policy has changed. This paper will examine this trend by considering what is counted as 'good' evidence, difficulties in translating evidence into policy and practice and how evidence interacts with principles. To illustrate these points the removal of gamete donor anonymity in the UK in 2005 and the debates that preceded this change in the law will be examined. It will be argued that evidence will only ever take us so far and attention should also be paid to the underlying principles that guide policy. The paper will conclude with suggestions for how underlying principles can be more rigorously used in policy formation.

Analysis of Multiallelic CNVs by Emulsion Haplotype Fusion PCR.

PubMed

Tyson, Jess; Armour, John A L

2017-01-01

Emulsion-fusion PCR recovers long-range sequence information by combining products in cis from individual genomic DNA molecules. Emulsion droplets act as very numerous small reaction chambers in which different PCR products from a single genomic DNA molecule are condensed into short joint products, to unite sequences in cis from widely separated genomic sites. These products can therefore provide information about the arrangement of sequences and variants at a larger scale than established long-read sequencing methods. The method has been useful in defining the phase of variants in haplotypes, the typing of inversions, and determining the configuration of sequence variants in multiallelic CNVs. In this description we outline the rationale for the application of emulsion-fusion PCR methods to the analysis of multiallelic CNVs, and give practical details for our own implementation of the method in that context.

CRTC1/MAML2 fusion transcript in central mucoepidermoid carcinoma of mandible--diagnostic and histogenetic implications.

PubMed

Bell, Diana; Holsinger, Christopher F; El-Naggar, Adel K

2010-12-01

Intraosseous salivary gland carcinomas are extremely rare, comprising only 2% to 3% of all mucoepidermoid carcinomas (MECs) reported. The t(11;19) translocation and its CRTC1/MAML1 fusion transcript have been identified in MEC at different sites and are believed to be associated with the development of a subset of these tumors. However, the status of the fusion transcript has not been reported in intraosseous MEC. Here, we report 3 examples of central MEC of the mandible, including a case with a history of primary retromolar MEC. Reverse transcriptase-polymerase chain reaction and DNA sequencing analyses of the microdissected components of these tumors were used for the detection and verification of the fusion transcript. We identified, for the first time, the t(11;19) fusion gene transcript in central MEC, including in the previous primary retromolar MEC. No fusion transcript was detected in the second primary noncentral MEC or in another central MEC. The results indicate that central MEC can manifest the fusion transcript. This finding may have diagnostic and histogenetic roles in the future analysis of this entity. Published by Elsevier Inc.

Quantitative Analysis of Lipid Droplet Fusion: Inefficient Steady State Fusion but Rapid Stimulation by Chemical Fusogens

PubMed Central

Murphy, Samantha; Martin, Sally; Parton, Robert G.

2010-01-01

Lipid droplets (LDs) are dynamic cytoplasmic organelles containing neutral lipids and bounded by a phospholipid monolayer. Previous studies have suggested that LDs can undergo constitutive homotypic fusion, a process linked to the inhibitory effects of fatty acids on glucose transporter trafficking. Using strict quantitative criteria for LD fusion together with refined light microscopic methods and real-time analysis, we now show that LDs in diverse cell types show low constitutive fusogenic activity under normal growth conditions. To investigate the possible modulation of LD fusion, we screened for agents that can trigger fusion. A number of pharmacological agents caused homotypic fusion of lipid droplets in a variety of cell types. This provided a novel cell system to study rapid regulated fusion between homotypic phospholipid monolayers. LD fusion involved an initial step in which the two adjacent membranes became continuous (<10 s), followed by the slower merging (100 s) of the neutral lipid cores to produce a single spherical LD. These fusion events were accompanied by changes to the LD surface organization. Measurements of LDs undergoing homotypic fusion showed that fused LDs maintained their initial volume, with a corresponding decrease in surface area suggesting rapid removal of membrane from the fused LD. This study provides estimates for the level of constitutive LD fusion in cells and questions the role of LD fusion in vivo. In addition, it highlights the extent of LD restructuring which occurs when homotypic LD fusion is triggered in a variety of cell types. PMID:21203462

Positive selection on human gamete-recognition genes

PubMed Central

Stover, Daryn A.; Guerra, Vanessa; Mozaffari, Sahar V.; Ober, Carole; Mugal, Carina F.; Kaj, Ingemar

2018-01-01

Coevolution of genes that encode interacting proteins expressed on the surfaces of sperm and eggs can lead to variation in reproductive compatibility between mates and reproductive isolation between members of different species. Previous studies in mice and other mammals have focused in particular on evidence for positive or diversifying selection that shapes the evolution of genes that encode sperm-binding proteins expressed in the egg coat or zona pellucida (ZP). By fitting phylogenetic models of codon evolution to data from the 1000 Genomes Project, we identified candidate sites evolving under diversifying selection in the human genes ZP3 and ZP2. We also identified one candidate site under positive selection in C4BPA, which encodes a repetitive protein similar to the mouse protein ZP3R that is expressed in the sperm head and binds to the ZP at fertilization. Results from several additional analyses that applied population genetic models to the same data were consistent with the hypothesis of selection on those candidate sites leading to coevolution of sperm- and egg-expressed genes. By contrast, we found no candidate sites under selection in a fourth gene (ZP1) that encodes an egg coat structural protein not directly involved in sperm binding. Finally, we found that two of the candidate sites (in C4BPA and ZP2) were correlated with variation in family size and birth rate among Hutterite couples, and those two candidate sites were also in linkage disequilibrium in the same Hutterite study population. All of these lines of evidence are consistent with predictions from a previously proposed hypothesis of balancing selection on epistatic interactions between C4BPA and ZP3 at fertilization that lead to the evolution of co-adapted allele pairs. Such patterns also suggest specific molecular traits that may be associated with both natural reproductive variation and clinical infertility. PMID:29340252

Registration and Fusion of Multiple Source Remotely Sensed Image Data

NASA Technical Reports Server (NTRS)

LeMoigne, Jacqueline

2004-01-01

Earth and Space Science often involve the comparison, fusion, and integration of multiple types of remotely sensed data at various temporal, radiometric, and spatial resolutions. Results of this integration may be utilized for global change analysis, global coverage of an area at multiple resolutions, map updating or validation of new instruments, as well as integration of data provided by multiple instruments carried on multiple platforms, e.g. in spacecraft constellations or fleets of planetary rovers. Our focus is on developing methods to perform fast, accurate and automatic image registration and fusion. General methods for automatic image registration are being reviewed and evaluated. Various choices for feature extraction, feature matching and similarity measurements are being compared, including wavelet-based algorithms, mutual information and statistically robust techniques. Our work also involves studies related to image fusion and investigates dimension reduction and co-kriging for application-dependent fusion. All methods are being tested using several multi-sensor datasets, acquired at EOS Core Sites, and including multiple sensors such as IKONOS, Landsat-7/ETM+, EO1/ALI and Hyperion, MODIS, and SeaWIFS instruments. Issues related to the coregistration of data from the same platform (i.e., AIRS and MODIS from Aqua) or from several platforms of the A-train (i.e., MLS, HIRDLS, OMI from Aura with AIRS and MODIS from Terra and Aqua) will also be considered.

Antibody-cytokine fusion proteins for treatment of cancer: engineering cytokines for improved efficacy and safety.

PubMed

Young, Patricia A; Morrison, Sherie L; Timmerman, John M

2014-10-01

The true potential of cytokine therapies in cancer treatment is limited by the inability to deliver optimal concentrations into tumor sites due to dose-limiting systemic toxicities. To maximize the efficacy of cytokine therapy, recombinant antibody-cytokine fusion proteins have been constructed by a number of groups to harness the tumor-targeting ability of monoclonal antibodies. The aim is to guide cytokines specifically to tumor sites where they might stimulate more optimal anti-tumor immune responses while avoiding the systemic toxicities of free cytokine therapy. Antibody-cytokine fusion proteins containing interleukin (IL)-2, IL-12, IL-21, tumor necrosis factor (TNF)α, and interferons (IFNs) α, β, and γ have been constructed and have shown anti-tumor activity in preclinical and early-phase clinical studies. Future priorities for development of this technology include optimization of tumor targeting, bioactivity of the fused cytokine, and choice of appropriate agents for combination therapies. This review is intended to serve as a framework for engineering an ideal antibody-cytokine fusion protein, focusing on previously developed constructs and their clinical trial results. Copyright © 2014 Elsevier Inc. All rights reserved.

Self-assessed performance improves statistical fusion of image labels

PubMed Central

Bryan, Frederick W.; Xu, Zhoubing; Asman, Andrew J.; Allen, Wade M.; Reich, Daniel S.; Landman, Bennett A.

2014-01-01

Purpose: Expert manual labeling is the gold standard for image segmentation, but this process is difficult, time-consuming, and prone to inter-individual differences. While fully automated methods have successfully targeted many anatomies, automated methods have not yet been developed for numerous essential structures (e.g., the internal structure of the spinal cord as seen on magnetic resonance imaging). Collaborative labeling is a new paradigm that offers a robust alternative that may realize both the throughput of automation and the guidance of experts. Yet, distributing manual labeling expertise across individuals and sites introduces potential human factors concerns (e.g., training, software usability) and statistical considerations (e.g., fusion of information, assessment of confidence, bias) that must be further explored. During the labeling process, it is simple to ask raters to self-assess the confidence of their labels, but this is rarely done and has not been previously quantitatively studied. Herein, the authors explore the utility of self-assessment in relation to automated assessment of rater performance in the context of statistical fusion. Methods: The authors conducted a study of 66 volumes manually labeled by 75 minimally trained human raters recruited from the university undergraduate population. Raters were given 15 min of training during which they were shown examples of correct segmentation, and the online segmentation tool was demonstrated. The volumes were labeled 2D slice-wise, and the slices were unordered. A self-assessed quality metric was produced by raters for each slice by marking a confidence bar superimposed on the slice. Volumes produced by both voting and statistical fusion algorithms were compared against a set of expert segmentations of the same volumes. Results: Labels for 8825 distinct slices were obtained. Simple majority voting resulted in statistically poorer performance than voting weighted by self-assessed performance

Enhanced image capture through fusion

NASA Technical Reports Server (NTRS)

Burt, Peter J.; Hanna, Keith; Kolczynski, Raymond J.

1993-01-01

Image fusion may be used to combine images from different sensors, such as IR and visible cameras, to obtain a single composite with extended information content. Fusion may also be used to combine multiple images from a given sensor to form a composite image in which information of interest is enhanced. We present a general method for performing image fusion and show that this method is effective for diverse fusion applications. We suggest that fusion may provide a powerful tool for enhanced image capture with broad utility in image processing and computer vision.

Positional effects of fusion partners on the yield and solubility of MBP fusion proteins

PubMed Central

Raran-Kurussi, Sreejith; Keefe, Karina; Waugh, David S.

2015-01-01

Escherichia coli maltose-binding protein (MBP) is exceptionally effective at promoting the solubility of its fusion partners. However, there are conflicting reports in the literature claiming that 1) MBP is an effective solubility enhancer only when it is joined to the N-terminus of an aggregation-prone passenger protein, and 2) MBP is equally effective when fused to either end of the passenger. Here, we endeavor to resolve this controversy by comparing the solubility of a diverse set of MBP fusion proteins that, unlike those analyzed in previous studies, are identical in every way except for the order of the two domains. The results indicate that fusion proteins with an N-terminal MBP provide an excellent solubility advantage along with more robust expression when compared to analogous fusions in which MBP is the C-terminal fusion partner. We find that only intrinsically soluble passenger proteins (i.e., those not requiring a solubility enhancer) are produced as soluble fusions when they precede MBP. We also report that even subtle differences in inter-domain linker sequences can influence the solubility of fusion proteins. PMID:25782741

Membrane Topology Mapping of the Na+-Pumping NADH: Quinone Oxidoreductase from Vibrio cholerae by PhoA- Green Fluorescent Protein Fusion Analysis▿

PubMed Central

Duffy, Ellen B.; Barquera, Blanca

2006-01-01

The membrane topologies of the six subunits of Na+-translocating NADH:quinone oxidoreductase (Na+-NQR) from Vibrio cholerae were determined by a combination of topology prediction algorithms and the construction of C-terminal fusions. Fusion expression vectors contained either bacterial alkaline phosphatase (phoA) or green fluorescent protein (gfp) genes as reporters of periplasmic and cytoplasmic localization, respectively. A majority of the topology prediction algorithms did not predict any transmembrane helices for NqrA. A lack of PhoA activity when fused to the C terminus of NqrA and the observed fluorescence of the green fluorescent protein C-terminal fusion confirm that this subunit is localized to the cytoplasmic side of the membrane. Analysis of four PhoA fusions for NqrB indicates that this subunit has nine transmembrane helices and that residue T236, the binding site for flavin mononucleotide (FMN), resides in the cytoplasm. Three fusions confirm that the topology of NqrC consists of two transmembrane helices with the FMN binding site at residue T225 on the cytoplasmic side. Fusion analysis of NqrD and NqrE showed almost mirror image topologies, each consisting of six transmembrane helices; the results for NqrD and NqrE are consistent with the topologies of Escherichia coli homologs YdgQ and YdgL, respectively. The NADH, flavin adenine dinucleotide, and Fe-S center binding sites of NqrF were localized to the cytoplasm. The determination of the topologies of the subunits of Na+-NQR provides valuable insights into the location of cofactors and identifies targets for mutagenesis to characterize this enzyme in more detail. The finding that all the redox cofactors are localized to the cytoplasmic side of the membrane is discussed. PMID:17041063

Evidence of a potential receptor-binding site on the Nipah virus G protein (NiV-G): identification of globular head residues with a role in fusion promotion and their localization on an NiV-G structural model.

PubMed

Guillaume, Vanessa; Aslan, Hamide; Ainouze, Michelle; Guerbois, Mathilde; Wild, T Fabian; Buckland, Robin; Langedijk, Johannes P M

2006-08-01

As a preliminary to the localization of the receptor-binding site(s) on the Nipah virus (NiV) glycoprotein (NiV-G), we have undertaken the identification of NiV-G residues that play a role in fusion promotion. To achieve this, we have used two strategies. First, as NiV and Hendra virus (HeV) share a common receptor and their cellular tropism is similar, we hypothesized that residues functioning in receptor attachment could be conserved between their respective G proteins. Our initial strategy was to target charged residues (which can be expected to be at the surface of the protein) conserved between the NiV-G and HeV-G globular heads. Second, we generated NiV variants that escaped neutralization by anti-NiV-G monoclonal antibodies (MAbs) that neutralize NiV both in vitro and in vivo, likely by blocking receptor attachment. The sequencing of such "escape mutants" identified NiV-G residues present in the epitopes to which the neutralizing MAbs are directed. Residues identified via these two strategies whose mutation had an effect on fusion promotion were localized on a new structural model for the NiV-G protein. Our results suggest that seven NiV-G residues, including one (E533) that was identified using both strategies, form a contiguous site on the top of the globular head that is implicated in ephrinB2 binding. This site commences near the shallow depression in the center of the top surface of the globular head and extends to the rim of the barrel-like structure on the top loops of beta-sheet 5. The topology of this site is strikingly similar to that proposed to form the SLAM receptor site on another paramyxovirus attachment protein, that of the measles virus hemagglutinin.

Evidence of a Potential Receptor-Binding Site on the Nipah Virus G Protein (NiV-G): Identification of Globular Head Residues with a Role in Fusion Promotion and Their Localization on an NiV-G Structural Model

PubMed Central

Guillaume, Vanessa; Aslan, Hamide; Ainouze, Michelle; Guerbois, Mathilde; Fabian Wild, T.; Buckland, Robin; Langedijk, Johannes P. M.

2006-01-01

As a preliminary to the localization of the receptor-binding site(s) on the Nipah virus (NiV) glycoprotein (NiV-G), we have undertaken the identification of NiV-G residues that play a role in fusion promotion. To achieve this, we have used two strategies. First, as NiV and Hendra virus (HeV) share a common receptor and their cellular tropism is similar, we hypothesized that residues functioning in receptor attachment could be conserved between their respective G proteins. Our initial strategy was to target charged residues (which can be expected to be at the surface of the protein) conserved between the NiV-G and HeV-G globular heads. Second, we generated NiV variants that escaped neutralization by anti-NiV-G monoclonal antibodies (MAbs) that neutralize NiV both in vitro and in vivo, likely by blocking receptor attachment. The sequencing of such “escape mutants” identified NiV-G residues present in the epitopes to which the neutralizing MAbs are directed. Residues identified via these two strategies whose mutation had an effect on fusion promotion were localized on a new structural model for the NiV-G protein. Our results suggest that seven NiV-G residues, including one (E533) that was identified using both strategies, form a contiguous site on the top of the globular head that is implicated in ephrinB2 binding. This site commences near the shallow depression in the center of the top surface of the globular head and extends to the rim of the barrel-like structure on the top loops of β-sheet 5. The topology of this site is strikingly similar to that proposed to form the SLAM receptor site on another paramyxovirus attachment protein, that of the measles virus hemagglutinin. PMID:16840334

Fusion or confusion: knowledge or nonsense?

NASA Astrophysics Data System (ADS)

Rothman, Peter L.; Denton, Richard V.

1991-08-01

The terms 'data fusion,' 'sensor fusion,' multi-sensor integration,' and 'multi-source integration' have been used widely in the technical literature to refer to a variety of techniques, technologies, systems, and applications which employ and/or combine data derived from multiple information sources. Applications of data fusion range from real-time fusion of sensor information for the navigation of mobile robots to the off-line fusion of both human and technical strategic intelligence data. The Department of Defense Critical Technologies Plan lists data fusion in the highest priority group of critical technologies, but just what is data fusion? The DoD Critical Technologies Plan states that data fusion involves 'the acquisition, integration, filtering, correlation, and synthesis of useful data from diverse sources for the purposes of situation/environment assessment, planning, detecting, verifying, diagnosing problems, aiding tactical and strategic decisions, and improving system performance and utility.' More simply states, sensor fusion refers to the combination of data from multiple sources to provide enhanced information quality and availability over that which is available from any individual source alone. This paper presents a survey of the state-of-the- art in data fusion technologies, system components, and applications. A set of characteristics which can be utilized to classify data fusion systems is presented. Additionally, a unifying mathematical and conceptual framework within which to understand and organize fusion technologies is described. A discussion of often overlooked issues in the development of sensor fusion systems is also presented.

Dicentric breakage at telomere fusions

PubMed Central

Pobiega, Sabrina; Marcand, Stéphane

2010-01-01

Nonhomologous end-joining (NHEJ) inhibition at telomeres ensures that native chromosome ends do not fuse together. But the occurrence and consequences of rare telomere fusions are not well understood. It is notably unclear whether a telomere fusion could be processed to restore telomere ends. Here we address the behavior of individual dicentrics formed by telomere fusion in the yeast Saccharomyces cerevisiae. Our approach was to first stabilize and amplify fusions between two chromosomes by temporarily inactivating one centromere. Next we analyzed dicentric breakage following centromere reactivation. Unexpectedly, dicentrics often break at the telomere fusions during progression through mitosis, a process that restores the parental chromosomes. This unforeseen result suggests a rescue pathway able to process telomere fusions and to back up NHEJ inhibition at telomeres. PMID:20360388

The Rab3A-22A Chimera Prevents Sperm Exocytosis by Stabilizing Open Fusion Pores.

PubMed

Quevedo, María F; Lucchesi, Ornella; Bustos, Matías A; Pocognoni, Cristian A; De la Iglesia, Paola X; Tomes, Claudia N

2016-10-28

At the final stage of exocytotis, a fusion pore opens between the plasma and a secretory vesicle membranes; typically, when the pore dilates the vesicle releases its cargo. Sperm contain a large dense-core secretory granule (the acrosome) whose contents are secreted by regulated exocytosis at fertilization. Minutes after the arrival of the triggering signal, the acrosomal and plasma membranes dock at multiple sites and fusion pores open at the contact points. It is believed that immediately afterward, fusion pores dilate spontaneously. Rab3A is an essential component of human sperm exocytotic machinery. Yet, recombinant, persistently active Rab3A halts calcium-triggered secretion when introduced after docking into streptolysin O-permeabilized cells; so does a Rab3A-22A chimera. Here, we applied functional assays, electron and confocal microscopy to show that the secretion blockage is due to the stabilization of open fusion pores. Other novel findings are that sperm SNAREs engage in α-SNAP/NSF-sensitive complexes at a post-fusion stage. Complexes are disentangled by these chaperons to achieve vesiculation and acrosomal contents release. Thus, post-fusion regulation of the pores determines their expansion and the success of the acrosome reaction. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Magnetized Target Fusion

NASA Technical Reports Server (NTRS)

Griffin, Steven T.

2002-01-01

Magnetized target fusion (MTF) is under consideration as a means of building a low mass, high specific impulse, and high thrust propulsion system for interplanetary travel. This unique combination is the result of the generation of a high temperature plasma by the nuclear fusion process. This plasma can then be deflected by magnetic fields to provide thrust. Fusion is initiated by a small traction of the energy generated in the magnetic coils due to the plasma's compression of the magnetic field. The power gain from a fusion reaction is such that inefficiencies due to thermal neutrons and coil losses can be overcome. Since the fusion reaction products are directly used for propulsion and the power to initiate the reaction is directly obtained from the thrust generation, no massive power supply for energy conversion is required. The result should be a low engine mass, high specific impulse and high thrust system. The key is to successfully initiate fusion as a proof-of-principle for this application. Currently MSFC is implementing MTF proof-of-principle experiments. This involves many technical details and ancillary investigations. Of these, selected pertinent issues include the properties, orientation and timing of the plasma guns and the convergence and interface development of the "pusher" plasma. Computer simulations of the target plasma's behavior under compression and the convergence and mixing of the gun plasma are under investigation. This work is to focus on the gun characterization and development as it relates to plasma initiation and repeatability.

Cholesterol suppresses membrane leakage by decreasing water penetrability.

PubMed

Bu, Bing; Crowe, Michael; Diao, Jiajie; Ji, Baohua; Li, Dechang

2018-06-13

Membrane fusion is a fundamental biological process that lies at the heart of enveloped virus infection, synaptic signaling, intracellular vesicle trafficking, gamete fertilization, and cell-cell fusion. Membrane fusion is initiated as two apposed membranes merge to a single bilayer called a hemifusion diaphragm. It is believed that the contents of the two fusing membranes are released through a fusion pore formed at the hemifusion diaphragm, and yet another possible pathway has been proposed in which an undefined pore may form outside the hemifusion diaphragm at the apposed membranes, leading to the so-called leaky fusion. Here, we performed all-atom molecular dynamics simulations to study the evolution of the hemifusion diaphragm structure with various lipid compositions. We found that the lipid cholesterol decreased water penetrability to inhibit leakage pore formation. Biochemical leakage experiments support these simulation results. This study may shed light on the underlying mechanism of the evolution pathways of the hemifusion structure, especially the understanding of content leakage during membrane fusion.

Fusion Power measurement at ITER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bertalot, L.; Barnsley, R.; Krasilnikov, V.

2015-07-01

Nuclear fusion research aims to provide energy for the future in a sustainable way and the ITER project scope is to demonstrate the feasibility of nuclear fusion energy. ITER is a nuclear experimental reactor based on a large scale fusion plasma (tokamak type) device generating Deuterium - Tritium (DT) fusion reactions with emission of 14 MeV neutrons producing up to 700 MW fusion power. The measurement of fusion power, i.e. total neutron emissivity, will play an important role for achieving ITER goals, in particular the fusion gain factor Q related to the reactor performance. Particular attention is given also tomore » the development of the neutron calibration strategy whose main scope is to achieve the required accuracy of 10% for the measurement of fusion power. Neutron Flux Monitors located in diagnostic ports and inside the vacuum vessel will measure ITER total neutron emissivity, expected to range from 1014 n/s in Deuterium - Deuterium (DD) plasmas up to almost 10{sup 21} n/s in DT plasmas. The neutron detection systems as well all other ITER diagnostics have to withstand high nuclear radiation and electromagnetic fields as well ultrahigh vacuum and thermal loads. (authors)« less

The specification and global reprogramming of histone epigenetic marks during gamete formation and early embryo development in C. elegans.

PubMed

Samson, Mark; Jow, Margaret M; Wong, Catherine C L; Fitzpatrick, Colin; Aslanian, Aaron; Saucedo, Israel; Estrada, Rodrigo; Ito, Takashi; Park, Sung-kyu Robin; Yates, John R; Chu, Diana S

2014-10-01

In addition to the DNA contributed by sperm and oocytes, embryos receive parent-specific epigenetic information that can include histone variants, histone post-translational modifications (PTMs), and DNA methylation. However, a global view of how such marks are erased or retained during gamete formation and reprogrammed after fertilization is lacking. To focus on features conveyed by histones, we conducted a large-scale proteomic identification of histone variants and PTMs in sperm and mixed-stage embryo chromatin from C. elegans, a species that lacks conserved DNA methylation pathways. The fate of these histone marks was then tracked using immunostaining. Proteomic analysis found that sperm harbor ∼2.4 fold lower levels of histone PTMs than embryos and revealed differences in classes of PTMs between sperm and embryos. Sperm chromatin repackaging involves the incorporation of the sperm-specific histone H2A variant HTAS-1, a widespread erasure of histone acetylation, and the retention of histone methylation at sites that mark the transcriptional history of chromatin domains during spermatogenesis. After fertilization, we show HTAS-1 and 6 histone PTM marks distinguish sperm and oocyte chromatin in the new embryo and characterize distinct paternal and maternal histone remodeling events during the oocyte-to-embryo transition. These include the exchange of histone H2A that is marked by ubiquitination, retention of HTAS-1, removal of the H2A variant HTZ-1, and differential reprogramming of histone PTMs. This work identifies novel and conserved features of paternal chromatin that are specified during spermatogenesis and processed in the embryo. Furthermore, our results show that different species, even those with diverged DNA packaging and imprinting strategies, use conserved histone modification and removal mechanisms to reprogram epigenetic information.

Gamete donors' reasons for, and expectations and experiences of, registration with a voluntary donor linking register.

PubMed

Blyth, Eric; Crawshaw, Marilyn; Frith, Lucy; van den Akker, Olga

2017-12-01

This paper reports on a study of the views and experiences of 21 sperm donors and five egg donors registered with UK DonorLink (UKDL), a voluntary DNA-based contact register established to facilitate contact between adults who wish to identify and locate others to whom they are genetically related following donor conception. Specifically, the paper examines donors' reasons for searching for, or making information about themselves available to donor-conceived offspring. Their expectations of registration with UKDL, experiences of being registered and finally, the experiences of those who had contacted donor-conceived offspring and other genetic relatives are investigated. While most respondents reported largely positive experiences of registration, the study found significant issues relating to concerns about donation, DNA testing, possible linking with offspring and expectations of any relationship that might be established with offspring that have implications for support, mediation and counselling. Research that puts the experiences, perceptions and interests of gamete donors as the central focus of study is a relatively recent phenomenon. This study contributes to this debate and highlights directions for future research in this area.

A sensitive HIV-1 envelope induced fusion assay identifies fusion enhancement of thrombin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, De-Chun; Zhong, Guo-Cai; Su, Ju-Xiang

2010-01-22

To evaluate the interaction between HIV-1 envelope glycoprotein (Env) and target cell receptors, various cell-cell-fusion assays have been developed. In the present study, we established a novel fusion system. In this system, the expression of the sensitive reporter gene, firefly luciferase (FL) gene, in the target cells was used to evaluate cell fusion event. Simultaneously, constitutively expressed Renilla luciferase (RL) gene was used to monitor effector cell number and viability. FL gave a wider dynamic range than other known reporters and the introduction of RL made the assay accurate and reproducible. This system is especially beneficial for investigation of potentialmore » entry-influencing agents, for its power of ruling out the false inhibition or enhancement caused by the artificial cell-number variation. As a case study, we applied this fusion system to observe the effect of a serine protease, thrombin, on HIV Env-mediated cell-cell fusion and have found the fusion enhancement activity of thrombin over two R5-tropic HIV strains.« less

National Fusion Collaboratory: Grid Computing for Simulations and Experiments

NASA Astrophysics Data System (ADS)

Greenwald, Martin

2004-05-01

The National Fusion Collaboratory Project is creating a computational grid designed to advance scientific understanding and innovation in magnetic fusion research by facilitating collaborations, enabling more effective integration of experiments, theory and modeling and allowing more efficient use of experimental facilities. The philosophy of FusionGrid is that data, codes, analysis routines, visualization tools, and communication tools should be thought of as network available services, easily used by the fusion scientist. In such an environment, access to services is stressed rather than portability. By building on a foundation of established computer science toolkits, deployment time can be minimized. These services all share the same basic infrastructure that allows for secure authentication and resource authorization which allows stakeholders to control their own resources such as computers, data and experiments. Code developers can control intellectual property, and fair use of shared resources can be demonstrated and controlled. A key goal is to shield scientific users from the implementation details such that transparency and ease-of-use are maximized. The first FusionGrid service deployed was the TRANSP code, a widely used tool for transport analysis. Tools for run preparation, submission, monitoring and management have been developed and shared among a wide user base. This approach saves user sites from the laborious effort of maintaining such a large and complex code while at the same time reducing the burden on the development team by avoiding the need to support a large number of heterogeneous installations. Shared visualization and A/V tools are being developed and deployed to enhance long-distance collaborations. These include desktop versions of the Access Grid, a highly capable multi-point remote conferencing tool and capabilities for sharing displays and analysis tools over local and wide-area networks.

Fusion of Enveloped Viruses in Endosomes

PubMed Central

White, Judith M.; Whittaker, Gary R.

2016-01-01

Ari Helenius launched the field of enveloped virus fusion in endosomes with a seminal paper in the Journal of Cell Biology in 1980. In the intervening years a great deal has been learned about the structures and mechanisms of viral membrane fusion proteins as well as about the endosomes in which different enveloped viruses fuse and the endosomal cues that trigger fusion. We now recognize three classes of viral membrane fusion proteins based on structural criteria and four mechanisms of fusion triggering. After reviewing general features of viral membrane fusion proteins and viral fusion in endosomes, we delve into three characterized mechanisms for viral fusion triggering in endosomes: by low pH, by receptor binding plus low pH, and by receptor binding plus the action of a protease. We end with a discussion of viruses that may employ novel endosomal fusion triggering mechanisms. A key take home message is that enveloped viruses that enter cells by fusing in endosomes traverse the endocytic pathway until they reach an endosome that has all of the environmental conditions (pH, proteases, ions, intracellular receptors, and lipid composition) to (if needed) prime and (in all cases) trigger the fusion protein and to support membrane fusion. PMID:26935856

Production of Viable Gametes without Meiosis in Maize Deficient for an ARGONAUTE Protein[W

PubMed Central

Singh, Manjit; Goel, Shalendra; Meeley, Robert B.; Dantec, Christelle; Parrinello, Hugues; Michaud, Caroline; Leblanc, Olivier; Grimanelli, Daniel

2011-01-01

Apomixis is a form of asexual reproduction through seeds in angiosperms. Apomictic plants bypass meiosis and fertilization, developing offspring that are genetically identical to their mother. In a genetic screen for maize (Zea mays) mutants mimicking aspects of apomixis, we identified a dominant mutation resulting in the formation of functional unreduced gametes. The mutant shows defects in chromatin condensation during meiosis and subsequent failure to segregate chromosomes. The mutated locus codes for AGO104, a member of the ARGONAUTE family of proteins. AGO104 accumulates specifically in somatic cells surrounding the female meiocyte, suggesting a mobile signal rather than cell-autonomous control. AGO104 is necessary for non-CG methylation of centromeric and knob-repeat DNA. Digital gene expression tag profiling experiments using high-throughput sequencing show that AGO104 influences the transcription of many targets in the ovaries, with a strong effect on centromeric repeats. AGO104 is related to Arabidopsis thaliana AGO9, but while AGO9 acts to repress germ cell fate in somatic tissues, AGO104 acts to repress somatic fate in germ cells. Our findings show that female germ cell development in maize is dependent upon conserved small RNA pathways acting non-cell-autonomously in the ovule. Interfering with this repression leads to apomixis-like phenotypes in maize. PMID:21325139

Feasibility study on sensor data fusion for the CP-140 aircraft: fusion architecture analyses

NASA Astrophysics Data System (ADS)

Shahbazian, Elisa

1995-09-01

Loral Canada completed (May 1995) a Department of National Defense (DND) Chief of Research and Development (CRAD) contract, to study the feasibility of implementing a multi- sensor data fusion (MSDF) system onboard the CP-140 Aurora aircraft. This system is expected to fuse data from: (a) attributed measurement oriented sensors (ESM, IFF, etc.); (b) imaging sensors (FLIR, SAR, etc.); (c) tracking sensors (radar, acoustics, etc.); (d) data from remote platforms (data links); and (e) non-sensor data (intelligence reports, environmental data, visual sightings, encyclopedic data, etc.). Based on purely theoretical considerations a central-level fusion architecture will lead to a higher performance fusion system. However, there are a number of systems and fusion architecture issues involving fusion of such dissimilar data: (1) the currently existing sensors are not designed to provide the type of data required by a fusion system; (2) the different types (attribute, imaging, tracking, etc.) of data may require different degree of processing, before they can be used within a fusion system efficiently; (3) the data quality from different sensors, and more importantly from remote platforms via the data links must be taken into account before fusing; and (4) the non-sensor data may impose specific requirements on the fusion architecture (e.g. variable weight/priority for the data from different sensors). This paper presents the analyses performed for the selection of the fusion architecture for the enhanced sensor suite planned for the CP-140 aircraft in the context of the mission requirements and environmental conditions.

Variability in Standard Outcomes of Posterior Lumbar Fusion Determined by National Databases.

PubMed

Joseph, Jacob R; Smith, Brandon W; Park, Paul

2017-01-01

National databases are used with increasing frequency in spine surgery literature to evaluate patient outcomes. The differences between individual databases in relationship to outcomes of lumbar fusion are not known. We evaluated the variability in standard outcomes of posterior lumbar fusion between the University HealthSystem Consortium (UHC) database and the Healthcare Cost and Utilization Project National Inpatient Sample (NIS). NIS and UHC databases were queried for all posterior lumbar fusions (International Classification of Diseases, Ninth Revision code 81.07) performed in 2012. Patient demographics, comorbidities (including obesity), length of stay (LOS), in-hospital mortality, and complications such as urinary tract infection, deep venous thrombosis, pulmonary embolism, myocardial infarction, durotomy, and surgical site infection were collected using specific International Classification of Diseases, Ninth Revision codes. Analysis included 21,470 patients from the NIS database and 14,898 patients from the UHC database. Demographic data were not significantly different between databases. Obesity was more prevalent in UHC (P = 0.001). Mean LOS was 3.8 days in NIS and 4.55 in UHC (P < 0.0001). Complications were significantly higher in UHC, including urinary tract infection, deep venous thrombosis, pulmonary embolism, myocardial infarction, surgical site infection, and durotomy. In-hospital mortality was similar between databases. NIS and UHC databases had similar demographic patient populations undergoing posterior lumbar fusion. However, the UHC database reported significantly higher complication rate and longer LOS. This difference may reflect academic institutions treating higher-risk patients; however, a definitive reason for the variability between databases is unknown. The inability to precisely determine the basis of the variability between databases highlights the limitations of using administrative databases for spinal outcome analysis. Copyright

Positional effects of fusion partners on the yield and solubility of MBP fusion proteins.

PubMed

Raran-Kurussi, Sreejith; Keefe, Karina; Waugh, David S

2015-06-01

Escherichia coli maltose-binding protein (MBP) is exceptionally effective at promoting the solubility of its fusion partners. However, there are conflicting reports in the literature claiming that (1) MBP is an effective solubility enhancer only when it is joined to the N-terminus of an aggregation-prone passenger protein, and (2) MBP is equally effective when fused to either end of the passenger. Here, we endeavor to resolve this controversy by comparing the solubility of a diverse set of MBP fusion proteins that, unlike those analyzed in previous studies, are identical in every way except for the order of the two domains. The results indicate that fusion proteins with an N-terminal MBP provide an excellent solubility advantage along with more robust expression when compared to analogous fusions in which MBP is the C-terminal fusion partner. We find that only intrinsically soluble passenger proteins (i.e., those not requiring a solubility enhancer) are produced as soluble fusions when they precede MBP. We also report that even subtle differences in inter-domain linker sequences can influence the solubility of fusion proteins. Published by Elsevier Inc.

Exo-endo cellulase fusion protein

DOEpatents

Bower, Benjamin S [Palo Alto, CA; Larenas, Edmund A [Palo Alto, CA; Mitchinson, Colin [Palo Alto, CA

2012-01-17

The present invention relates to a heterologous exo-endo cellulase fusion construct, which encodes a fusion protein having cellulolytic activity comprising a catalytic domain derived from a fungal exo-cellobiohydrolase and a catalytic domain derived from an endoglucanase. The invention also relates to vectors and fungal host cells comprising the heterologous exo-endo cellulase fusion construct as well as methods for producing a cellulase fusion protein and enzymatic cellulase compositions.

Two Strategic Decisions Facing Fusion

NASA Astrophysics Data System (ADS)

Baldwin, D. E.

1998-06-01

Two strategic decisions facing the U.S. fusion program are described. The first decision deals with the role and rationale of the tokamak within the U. S. fusion program, and it underlies the debate over our continuing role in the evolving ITER collaboration (mid-1998). The second decision concerns how to include Inertial Fusion Energy (IFE) as a viable part of the national effort to harness fusion energy.

Frontier of Fusion Research: Path to the Steady State Fusion Reactor by Large Helical Device

NASA Astrophysics Data System (ADS)

Motojima, Osamu

2006-12-01

The ITER, the International Thermonuclear Experimental Reactor, which will be built in Cadarache in France, has finally started this year, 2006. Since the thermal energy produced by fusion reactions divided by the external heating power, i.e., the Q value, will be larger than 10, this is a big step of the fusion research for half a century trying to tame the nuclear fusion for the 6.5 Billion people on the Earth. The source of the Sun's power is lasting steadily and safely for 8 Billion years. As a potentially safe environmentally friendly and economically competitive energy source, fusion should provide a sustainable future energy supply for all mankind for ten thousands of years. At the frontier of fusion research important milestones are recently marked on a long road toward a true prototype fusion reactor. In its own merits, research into harnessing turbulent burning plasmas and thereby controlling fusion reaction, is one of the grand challenges of complex systems science. After a brief overview of a status of world fusion projects, a focus is given on fusion research at the National Institute for Fusion Science (NIFS) in Japan, which is playing a role of the Inter University Institute, the coordinating Center of Excellence for academic fusion research and by the Large Helical Device (LHD), the world's largest superconducting heliotron device, as a National Users' facility. The current status of LHD project is presented focusing on the experimental program and the recent achievements in basic parameters and in steady state operations. Since, its start in a year 1998, a remarkable progress has presently resulted in the temperature of 140 Million degree, the highest density of 500 Thousand Billion/cc with the internal density barrier (IDB) and the highest steady average beta of 4.5% in helical plasma devices and the largest total input energy of 1.6 GJ, in all magnetic confinement fusion devices. Finally, a perspective is given of the ITER Broad Approach program

The dengue virus type 2 envelope protein fusion peptide is essential for membrane fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Claire Y.-H., E-mail: CHuang1@cdc.go; Butrapet, Siritorn; Moss, Kelly J.

The flaviviral envelope (E) protein directs virus-mediated membrane fusion. To investigate membrane fusion as a requirement for virus growth, we introduced 27 unique mutations into the fusion peptide of an infectious cDNA clone of dengue 2 virus and recovered seven stable mutant viruses. The fusion efficiency of the mutants was impaired, demonstrating for the first time the requirement for specific FP AAs in optimal fusion. Mutant viruses exhibited different growth kinetics and/or genetic stabilities in different cell types and adult mosquitoes. Virus particles could be recovered following RNA transfection of cells with four lethal mutants; however, recovered viruses could notmore » re-infect cells. These viruses could enter cells, but internalized virus appeared to be retained in endosomal compartments of infected cells, thus suggesting a fusion blockade. Mutations of the FP also resulted in reduced virus reactivity with flavivirus group-reactive antibodies, confirming earlier reports using virus-like particles.« less

Nighttime images fusion based on Laplacian pyramid

NASA Astrophysics Data System (ADS)

Wu, Cong; Zhan, Jinhao; Jin, Jicheng

2018-02-01

This paper expounds method of the average weighted fusion, image pyramid fusion, the wavelet transform and apply these methods on the fusion of multiple exposures nighttime images. Through calculating information entropy and cross entropy of fusion images, we can evaluate the effect of different fusion. Experiments showed that Laplacian pyramid image fusion algorithm is suitable for processing nighttime images fusion, it can reduce the halo while preserving image details.

Fusion of disubstituted benzenes.

PubMed

Martin, E; Yalkowsky, S H; Wells, J E

1979-05-01

The entropy of fusion of 84 disubstituted benzenes was essentially constant and independent of the participation of the compounds in intramolecular or intermolecular hydrogen bonding. It was also independent of the shapes, sizes, and dipole moments of the rigid molecules studied. While the entropy of fusion was independent of these parameters, the melting point and the heat of fusion showed a direct dependence on molecular properties.

Comparison of instrumented anterior interbody fusion with instrumented circumferential lumbar fusion.

PubMed

Madan, S S; Boeree, N R

2003-12-01

Posterior lumbar interbody fusion (PLIF) restores disc height, the load bearing ability of anterior ligaments and muscles, root canal dimensions, and spinal balance. It immobilizes the painful degenerate spinal segment and decompresses the nerve roots. Anterior lumbar interbody fusion (ALIF) does the same, but could have complications of graft extrusion, compression and instability contributing to pseudarthrosis in the absence of instrumentation. The purpose of this study was to assess and compare the outcome of instrumented circumferential fusion through a posterior approach [PLIF and posterolateral fusion (PLF)] with instrumented ALIF using the Hartshill horseshoe cage, for comparable degrees of internal disc disruption and clinical disability. It was designed as a prospective study, comparing the outcome of two methods of instrumented interbody fusion for internal disc disruption. Between April 1994 and June 1998, the senior author (N.R.B.) performed 39 instrumented ALIF procedures and 35 instrumented circumferential fusion with PLIF procedures. The second author, an independent assessor (S.M.), performed the entire review. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging (MRI) and provocative discography in all the patients. The outcome in the two groups was compared in terms of radiological improvement and clinical improvement, measured on the basis of improvement of back pain and work capacity. Preoperatively, patients were asked to fill out a questionnaire giving their demographic details, maximum walking distance and current employment status in order to establish the comparability of the two groups. Patient assessment was with the Oswestry Disability Index, quality of life questionnaire (subjective), pain drawing, visual analogue scale, disability benefit, compensation status, and psychological profile. The results of the study showed a satisfactory outcome (score< or =30) on the subjective (quality of life

Preparation of GST Fusion Proteins.

PubMed

Einarson, Margret B; Pugacheva, Elena N; Orlinick, Jason R

2007-04-01

INTRODUCTIONThis protocol describes the preparation of glutathione-S-transferase (GST) fusion proteins, which have had a wide range of applications since their introduction as tools for synthesis of recombinant proteins in bacteria. GST was originally selected as a fusion moiety because of several desirable properties. First and foremost, when expressed in bacteria alone, or as a fusion, GST is not sequestered in inclusion bodies (in contrast to previous fusion protein systems). Second, GST can be affinity-purified without denaturation because it binds to immobilized glutathione, which provides the basis for simple purification. Consequently, GST fusion proteins are routinely used for antibody generation and purification, protein-protein interaction studies, and biochemical analysis.

Fusion energy

NASA Astrophysics Data System (ADS)

1990-09-01

The main purpose of the International Thermonuclear Experimental Reactor (ITER) is to develop an experimental fusion reactor through the united efforts of many technologically advanced countries. The ITER terms of reference, issued jointly by the European Community, Japan, the USSR, and the United States, call for an integrated international design activity and constitute the basis of current activities. Joint work on ITER is carried out under the auspices of the International Atomic Energy Agency (IAEA), according to the terms of quadripartite agreement reached between the European Community, Japan, the USSR, and the United States. The site for joint technical work sessions is at the Max Planck Institute of Plasma Physics. Garching, Federal Republic of Germany. The ITER activities have two phases: a definition phase performed in 1988 and the present design phase (1989 to 1990). During the definition phase, a set of ITER technical characteristics and supporting research and development (R and D) activities were developed and reported. The present conceptual design phase of ITER lasts until the end of 1990. The objectives of this phase are to develop the design of ITER, perform a safety and environmental analysis, develop site requirements, define future R and D needs, and estimate cost, manpower, and schedule for construction and operation. A final report will be submitted at the end of 1990. This paper summarizes progress in the ITER program during the 1989 design phase.

Estimating the melting point, entropy of fusion, and enthalpy of fusion of organic compounds via SPARC.

PubMed

Whiteside, T S; Hilal, S H; Brenner, A; Carreira, L A

2016-08-01

The entropy of fusion, enthalpy of fusion, and melting point of organic compounds can be estimated through three models developed using the SPARC (SPARC Performs Automated Reasoning in Chemistry) platform. The entropy of fusion is modelled through a combination of interaction terms and physical descriptors. The enthalpy of fusion is modelled as a function of the entropy of fusion, boiling point, and flexibility of the molecule. The melting point model is the enthalpy of fusion divided by the entropy of fusion. These models were developed in part to improve SPARC's vapour pressure and solubility models. These models have been tested on 904 unique compounds. The entropy model has a RMS of 12.5 J mol(-1) K(-1). The enthalpy model has a RMS of 4.87 kJ mol(-1). The melting point model has a RMS of 54.4°C.

Kinetic advantage of controlled intermediate nuclear fusion

NASA Astrophysics Data System (ADS)

Guo, Xiaoming

2012-09-01

The dominated process of controlled fusion is to let nuclei gain enough kinetic energy to overcome Coulomb barrier. As a result, a fusion scheme can consider two factors in its design: to increase kinetic energy of nuclei and to alter the Coulomb barrier. Cold Fusion and Hot fusion are all one-factor schemes while Intermediate Fusion is a twofactors scheme. This made CINF kinetically superior. Cold Fusion reduces deuteron-deuteron distance, addressing Coulomb barrier, and Hot Fusion heat up plasma into extreme high temperature, addressing kinetic energy. Without enough kinetic energy made Cold Fusion skeptical. Extreme high temperature made Hot Fusion very difficult to engineer. Because CIFN addresses both factors, CIFN is a more promising technique to be industrialized.

Altered visual sensory fusion in children with reading difficulties.

PubMed

González-Castro, P; Rodríguez, C; Núñez, J C; Vallejo, G; González-Pienda, J A

2014-12-01

Reading is a multi-sensory and multi-cognitive task, and its difficulties (e.g., dyslexia) are not a unitary disorder. There are probably a variety of manifestations that relate to the actual site of impairment. A randomized, pre-test/post-test nonequivalent-groups design was conducted over 4 months with three groups aged between 6 and 8 years. One group comprised 76 participants (34 boys, 42 girls) with reading difficulties and altered sensory fusion (RD+ASF), a second group was made up of 123 students (59 boys, 64 girls) with reading difficulties but without altered sensory fusion (RD), and a third group comprised 81 participants (39 boys, 42 girls) who were young readers (RL) without reading delay, paired with the RD group on reading level. The experimental groups received intervention in the skills of control, stimulus recognition, and phonological awareness during a 4-month period. Both pre-test and post-test measures of errors in reading mechanics and reading routes (word and pseudo-word) were obtained. Poorer results in mechanics and reading routes of the RD+ASF group suggest that the effectiveness of the intervention depended on the characteristics of the groups and on the presence of sensory fusion deficits in the RD students.

Construction of transformed, cultured silkworm cells and transgenic silkworm using the site-specific integrase system from phage φC31.

PubMed

Yin, Yajuan; Cao, Guangli; Xue, Renyu; Gong, Chengliang

2014-10-01

The Streptomyces bacteriophage, φC31, uses a site-specific integrase enzyme to perform efficient recombination. The recombination system uses specific sequences to integrate exogenous DNA from the phage into a host. The sequences are known as the attP site in the phage and the attB site in the host. The system can be used as a genetic manipulation tool. In this study it has been applied to the transformation of cultured BmN cells and the construction of transgenic Bombyx mori individuals. A plasmid, pSK-attB/Pie1-EGFP/Zeo-PASV40, containing a cassette designed to express a egfp-zeocin fusion gene, was co-transfected into cultured BmN cells with a helper plasmid, pSK-Pie1/NLS-Int/NSL. Expression of the egfp-zeocin fusion gene was driven by an ie-1 promoter, downstream of a φC31 attB site. The helper plasmid encoded the φC31 integrase enzyme, which was flanked by two nuclear localization signals. Expression of the egfp-zeocin fusion gene could be observed in transformed cells. The two plasmids were also transferred into silkworm eggs to obtain transgenic silkworms. Successful integration of the fusion gene was indicated by the detection of green fluorescence, which was emitted by the silkworms. Nucleotide sequence analysis demonstrated that the attB site had been cut, to allow recombination between the attB and endogenous pseudo attP sites in the cultured silkworm cells and silkworm individuals.

Multi-sensor fusion over the World Trade Center disaster site

NASA Astrophysics Data System (ADS)

Rodarmel, Craig; Scott, Lawrence; Simerlink, Deborah A.; Walker, Jeffrey

2002-09-01

The immense size and scope of the rescue and clean-up of the World Trade Center site created a need for data that would provide a total overview of the disaster area. To fulfill this need, the New York State Office for Technology (NYSOFT) contracted with EarthData International to collect airborne remote sensing data over Ground Zero with an airborne light detection and ranging (LIDAR) sensor, a high-resolution digital camera, and a thermal camera. The LIDAR data provided a three-dimensional elevation model of the ground surface that was used for volumetric calculations and also in the orthorectification of the digital images. The digital camera provided high-resolution imagery over the site to aide the rescuers in placement of equipment and other assets. In addition, the digital imagery was used to georeference the thermal imagery and also provided the visual background for the thermal data. The thermal camera aided in the location and tracking of underground fires. The combination of data from these three sensors provided the emergency crews with a timely, accurate overview containing a wealth of information of the rapidly changing disaster site. Because of the dynamic nature of the site, the data was acquired on a daily basis, processed, and turned over to NYSOFT within twelve hours of the collection. During processing, the three datasets were combined and georeferenced to allow them to be inserted into the client's geographic information systems.

Robotics and local fusion

NASA Astrophysics Data System (ADS)

Emmerman, Philip J.

2005-05-01

Teams of robots or mixed teams of warfighters and robots on reconnaissance and other missions can benefit greatly from a local fusion station. A local fusion station is defined here as a small mobile processor with interfaces to enable the ingestion of multiple heterogeneous sensor data and information streams, including blue force tracking data. These data streams are fused and integrated with contextual information (terrain features, weather, maps, dynamic background features, etc.), and displayed or processed to provide real time situational awareness to the robot controller or to the robots themselves. These blue and red force fusion applications remove redundancies, lessen ambiguities, correlate, aggregate, and integrate sensor information with context such as high resolution terrain. Applications such as safety, team behavior, asset control, training, pattern analysis, etc. can be generated or enhanced by these fusion stations. This local fusion station should also enable the interaction between these local units and a global information world.

Pain and functional improvement effects of methylene blue injection on the soft tissue around fusion site after traumatic thoracolumbar fixation: A double-blind, randomized placebo-controlled study.

PubMed

Farrokhi, Majid Reza; Yazdanpanah, Hamed; Gholami, Mehrnaz; Farrokhi, Farnaz; Mesbahi, Amir Reza

2016-11-01

Fractures of the thoracolumbar spine can cause pain, long-term reductions in quality of life (QOL), and neural deficits. The aim of this study was to investigate the effects of methylene blue (MB) on preventing postoperative pain and improving QOL in patients with throracolumbar fractures undergoing posterior pedicle screw fixation. Fifty patients underwent standard posterior pedicular screw fixation for stabilization of the thoracolumbar fractures: 25 received 1ml of MB solution at a concentration of 0.5% and 25 received normal saline on the soft tissue around fusion site. Primary outcomes were the control of pain, evaluated at 48h, 2 and 6 months after surgery with the use of a visual analog scale (VAS), and the improvement of QOL, assessed 2 and 6 months postoperatively by means of Oswestry Disability Index (ODI) questionnaire. The mean VAS scores for pain were significantly lower in the MB group compared with the control group at 2 months (1.30±0.45 vs. 2.60±1.19, P<0.001) and 6 months (1.17±0.37 vs. 1.60±0.87; P=0.028) after treatment. At 2 months after the surgery, the mean ODI score was significantly lower in the MB-treated patients than the control group (20.4±10.92 vs. 34.8±15.11; P=0.001). The ODI score in the MB-treated patients was better than the control group at 6 months after the surgery (12.2±11.66 vs. 20.8±11.14; P=0.016). A single dose of MB on the soft tissue around fusion site shows promising results in terms of safety, reduction of postoperative pain, and functional results when compared with placebo 6 months after surgery. Copyright © 2016 Elsevier B.V. All rights reserved.

Fusion gamma diagnostics

NASA Astrophysics Data System (ADS)

Medley, S. S.; Cecil, F. E.; Cole, D.; Conway, M. A.; Wilkinson, F. J., III

1985-05-01

Nuclear reactions of interest in fusion research often possess a branch yielding prompt emission of gamma radiation in excess of 15 MeV which can be exploited to provide a new fusion reaction diagnostic having applications similar to conventional neutron emission measurements. Conceptual aspects of fusion gamma diagnostics are discussed with emphasis on application to the Tokamak Fusion Test Reactor (TFTR) during deuterium neutral beam heating of D-T and D-3He plasmas. Recent measurements of the D (T, γ)5He, D(3He, γ)5Li, and D(D, γ)4He branching ratios at low center-of-mass energy (30-100 keV) and of the response of a large volume Ne226 detector for gamma detection in high neutron backgrounds are presented. Using a well-shielded Ne226 detector during 20 MW-120 kV deuterium beam heating of a tritium plasma in TFTR, the D(T, γ)5He gamma signal level is estimated to be 3.5×105 cps.

Does reducing gamete co-incubation time improve clinical outcomes: a retrospective study.

PubMed

Li, Rui-Qi; Ouyang, Neng-Yong; Ou, Song-Bang; Ni, Ren-Min; Mai, Mei-Qi; Zhang, Qing-Xue; Yang, Dong-Zi; Wang, Wen-Jun

2016-01-01

The objective of this retrospective study was to determine whether patients undergoing in vitro fertilization (IVF) benefit from reducing the gamete co-incubation time. Patients (n = 570) were enrolled, including 281 patients in the reduced incubation time group (2-h incubation) and 289 patients in the standard IVF group (18-h incubation). The observed outcomes, including the clinical pregnancy rate (CPR), implantation rate (IR), live birth rate (LBR), and miscarriage rate (MR), were similar between the two groups. When the data were divided into two subgroups based on the maternal age (≤30 and >30 years), the rates of top-quality embryos (30.83 vs. 25.89 %; p = 0.028), CPR (66.67 vs. 42.11 %; p = 0.013), and IR (41.90 vs. 31.25 %, p = 0.019) of the 2-h incubation group were significantly higher in the younger subgroup. However, for older patients, only a lower MR (7.59 vs. 20.83 %; p = 0.019) was achieved. Reducing the time of incubation still improved the CPR (OR = 1.993, 95 % CI 1.141-3.480) and MR (OR = 3.173, 95 % CI 1.013-9.936) in the younger and older subgroups, respectively, after it was adjusted for potential confounders. Reducing incubation time improves the clinical results of IVF, although the LBR is not statistically different between the 2- and 18-h incubation time groups. And the specific clinical outcomes of reducing incubation time varied between the >30-year-old and the ≤30-year-old.

Inertial-confinement fusion with lasers

NASA Astrophysics Data System (ADS)

Betti, R.; Hurricane, O. A.

2016-05-01

The quest for controlled fusion energy has been ongoing for over a half century. The demonstration of ignition and energy gain from thermonuclear fuels in the laboratory has been a major goal of fusion research for decades. Thermonuclear ignition is widely considered a milestone in the development of fusion energy, as well as a major scientific achievement with important applications in national security and basic sciences. The US is arguably the world leader in the inertial confinement approach to fusion and has invested in large facilities to pursue it, with the objective of establishing the science related to the safety and reliability of the stockpile of nuclear weapons. Although significant progress has been made in recent years, major challenges still remain in the quest for thermonuclear ignition via laser fusion. Here, we review the current state of the art in inertial confinement fusion research and describe the underlying physical principles.

Pedicle screw fixation for isthmic spondylolisthesis: does posterior lumbar interbody fusion improve outcome over posterolateral fusion?

PubMed

La Rosa, Giovanni; Conti, Alfredo; Cacciola, Fabio; Cardali, Salvatore; La Torre, Domenico; Gambadauro, Nicola Maria; Tomasello, Francesco

2003-09-01

Posterolateral fusion involving instrumentation-assisted segmental fixation represents a valid procedure in the treatment of lumbar instability. In cases of anterior column failure, such as in isthmic spondylolisthesis, supplemental posterior lumbar interbody fusion (PLIF) may improve the fusion rate and endurance of the construct. Posterior lumbar interbody fusion is, however, a more demanding procedure and increases costs and risks of the intervention. The advantages of this technique must, therefore, be weighed against those of a simple posterior lumbar fusion. Thirty-five consecutive patients underwent pedicle screw fixation for isthmic spondylolisthesis. In 18 patients posterior lumbar fusion was performed, and in 17 patients PLIF was added. Clinical, economic, functional, and radiographic data were assessed to determine differences in clinical and functional results and biomechanical properties. At 2-year follow-up examination, the correction of subluxation, disc height, and foraminal area were maintained in the group in which a PLIF procedure was performed, but not in the posterolateral fusion-only group (p < 0.05). Nevertheless, no statistical intergroup differences were demonstrated in terms of neurological improvement (p = 1), economic (p = 0.43), or functional (p = 0.95) outcome, nor in terms of fusion rate (p = 0.49). The authors' findings support the view that an interbody fusion confers superior mechanical strength to the spinal construct; when posterolateral fusion is the sole intervention, progressive loss of the extreme correction can be expected. Such mechanical insufficiency, however, did not influence clinical outcome.

Disc replacement adjacent to cervical fusion: a biomechanical comparison of hybrid construct versus two-level fusion.

PubMed

Lee, Michael J; Dumonski, Mark; Phillips, Frank M; Voronov, Leonard I; Renner, Susan M; Carandang, Gerard; Havey, Robert M; Patwardhan, Avinash G

2011-11-01

A cadaveric biomechanical study. To investigate the biomechanical behavior of the cervical spine after cervical total disc replacement (TDR) adjacent to a fusion as compared to a two-level fusion. There are concerns regarding the biomechanical effects of cervical fusion on the mobile motion segments. Although previous biomechanical studies have demonstrated that cervical disc replacement normalizes adjacent segment motion, there is a little information regarding the function of a cervical disc replacement adjacent to an anterior cervical decompression and fusion, a potentially common clinical application. Nine cadaveric cervical spines (C3-T1, age: 60.2 ± 3.5 years) were tested under load- and displacement-control testing. After intact testing, a simulated fusion was performed at C4-C5, followed by C6-C7. The simulated fusion was then reversed, and the response of TDR at C5-C6 was measured. A hybrid construct was then tested with the TDR either below or above a single-level fusion and contrasted with a simulated two-level fusion (C4-C6 and C5-C7). The external fixator device used to simulate fusion significantly reduced range of motion (ROM) at C4-C5 and C6-C7 by 74.7 ± 8.1% and 78.1 ± 11.5%, respectively (P < 0.05). Removal of the fusion construct restored the motion response of the spinal segments to their intact state. Arthroplasty performed at C5-C6 using the porous-coated motion disc prosthesis maintained the total flexion-extension ROM to the level of the intact controls when used as a stand-alone procedure or when implanted adjacent to a single-level fusion (P > 0.05). The location of the single-level fusion, whether above or below the arthroplasty, did not significantly affect the motion response of the arthroplasty in the hybrid construct. Performing a two-level fusion significantly increased the motion demands on the nonoperated segments as compared to a hybrid TDR-plus fusion construct when the spine was required to reach the same motion end points

A single amino acid change, Q114R, in the cleavage-site sequence of Newcastle disease virus fusion protein attenuates viral replication and pathogenicity.

PubMed

Samal, Sweety; Kumar, Sachin; Khattar, Sunil K; Samal, Siba K

2011-10-01

A key determinant of Newcastle disease virus (NDV) virulence is the amino acid sequence at the fusion (F) protein cleavage site. The NDV F protein is synthesized as an inactive precursor, F(0), and is activated by proteolytic cleavage between amino acids 116 and 117 to produce two disulfide-linked subunits, F(1) and F(2). The consensus sequence of the F protein cleavage site of virulent [(112)(R/K)-R-Q-(R/K)-R↓F-I(118)] and avirulent [(112)(G/E)-(K/R)-Q-(G/E)-R↓L-I(118)] strains contains a conserved glutamine residue at position 114. Recently, some NDV strains from Africa and Madagascar were isolated from healthy birds and have been reported to contain five basic residues (R-R-R-K-R↓F-I/V or R-R-R-R-R↓F-I/V) at the F protein cleavage site. In this study, we have evaluated the role of this conserved glutamine residue in the replication and pathogenicity of NDV by using the moderately pathogenic Beaudette C strain and by making Q114R, K115R and I118V mutants of the F protein in this strain. Our results showed that changing the glutamine to a basic arginine residue reduced viral replication and attenuated the pathogenicity of the virus in chickens. The pathogenicity was further reduced when the isoleucine at position 118 was substituted for valine.

Molecular Evolution of Respiratory Syncytial Virus Fusion Gene, Canada, 2006–2010

PubMed Central

Papenburg, Jesse; Carbonneau, Julie; Hamelin, Marie-Ève; Isabel, Sandra; Bouhy, Xavier; Ohoumanne, Najwa; Déry, Pierre; Paes, Bosco A.; Corbeil, Jacques; Bergeron, Michel G.; De Serres, Gaston

2012-01-01

To assess molecular evolution of the respiratory syncytial virus (RSV) fusion gene, we analyzed RSV-positive specimens from 123 children in Canada who did or did not receive RSV immunoprophylaxis (palivizumab) during 2006–2010. Resistance-conferring mutations within the palivizumab binding site occurred in 8.7% of palivizumab recipients and none of the nonrecipients. PMID:22264682

Controlled Nuclear Fusion.

ERIC Educational Resources Information Center

Glasstone, Samuel

This publication is one of a series of information booklets for the general public published by The United States Atomic Energy Commission. Among the topics discussed are: Importance of Fusion Energy; Conditions for Nuclear Fusion; Thermonuclear Reactions in Plasmas; Plasma Confinement by Magnetic Fields; Experiments With Plasmas; High-Temperature…

Construction of hybrid peptide synthetases by module and domain fusions

PubMed Central

Mootz, Henning D.; Schwarzer, Dirk; Marahiel, Mohamed A.

2000-01-01

Nonribosomal peptide synthetases are modular enzymes that assemble peptides of diverse structures and important biological activities. Their modular organization provides a great potential for the rational design of novel compounds by recombination of the biosynthetic genes. Here we describe the extension of a dimodular system to trimodular ones based on whole-module fusion. The recombinant hybrid enzymes were purified to monitor product assembly in vitro. We started from the first two modules of tyrocidine synthetase, which catalyze the formation of the dipeptide dPhe-Pro, to construct such hybrid systems. Fusion of the second, proline-specific module with the ninth and tenth modules of the tyrocidine synthetases, specific for ornithine and leucine, respectively, resulted in dimodular hybrid enzymes exhibiting the combined substrate specificities. The thioesterase domain was fused to the terminal module. Upon incubation of these dimodular enzymes with the first tyrocidine module, TycA, incorporating dPhe, the predicted tripeptides dPhe-Pro-Orn and dPhe-Pro-Leu were obtained at rates of 0.15 min-1 and 2.1 min-1. The internal thioesterase domain was necessary and sufficient to release the products from the hybrid enzymes and thereby facilitate a catalytic turnover. Our approach of whole-module fusion is based on an improved definition of the fusion sites and overcomes the recently discovered editing function of the intrinsic condensation domains. The stepwise construction of hybrid peptide synthetases from catalytic subunits reinforces the inherent potential for the synthesis of novel, designed peptides. PMID:10811885

Construction of hybrid peptide synthetases by module and domain fusions.

PubMed

Mootz, H D; Schwarzer, D; Marahiel, M A

2000-05-23

Nonribosomal peptide synthetases are modular enzymes that assemble peptides of diverse structures and important biological activities. Their modular organization provides a great potential for the rational design of novel compounds by recombination of the biosynthetic genes. Here we describe the extension of a dimodular system to trimodular ones based on whole-module fusion. The recombinant hybrid enzymes were purified to monitor product assembly in vitro. We started from the first two modules of tyrocidine synthetase, which catalyze the formation of the dipeptide dPhe-Pro, to construct such hybrid systems. Fusion of the second, proline-specific module with the ninth and tenth modules of the tyrocidine synthetases, specific for ornithine and leucine, respectively, resulted in dimodular hybrid enzymes exhibiting the combined substrate specificities. The thioesterase domain was fused to the terminal module. Upon incubation of these dimodular enzymes with the first tyrocidine module, TycA, incorporating dPhe, the predicted tripeptides dPhe-Pro-Orn and dPhe-Pro-Leu were obtained at rates of 0.15 min(-1) and 2.1 min(-1). The internal thioesterase domain was necessary and sufficient to release the products from the hybrid enzymes and thereby facilitate a catalytic turnover. Our approach of whole-module fusion is based on an improved definition of the fusion sites and overcomes the recently discovered editing function of the intrinsic condensation domains. The stepwise construction of hybrid peptide synthetases from catalytic subunits reinforces the inherent potential for the synthesis of novel, designed peptides.

3D Image Fusion to Localise Intercostal Arteries During TEVAR.

PubMed

Koutouzi, G; Sandström, C; Skoog, P; Roos, H; Falkenberg, M

2017-01-01

Preservation of intercostal arteries during thoracic aortic procedures reduces the risk of post-operative paraparesis. The origins of the intercostal arteries are visible on pre-operative computed tomography angiography (CTA), but rarely on intra-operative angiography. The purpose of this report is to suggest an image fusion technique for intra-operative localisation of the intercostal arteries during thoracic endovascular repair (TEVAR). The ostia of the intercostal arteries are identified and manually marked with rings on the pre-operative CTA. The optimal distal landing site in the descending aorta is determined and marked, allowing enough length for an adequate seal and attachment without covering more intercostal arteries than necessary. After 3D/3D fusion of the pre-operative CTA with an intra-operative cone-beam CT (CBCT), the markings are overlaid on the live fluoroscopy screen for guidance. The accuracy of the overlay is confirmed with digital subtraction angiography (DSA) and the overlay is adjusted when needed. Stent graft deployment is guided by the markings. The initial experience of this technique in seven patients is presented. 3D image fusion was feasible in all cases. Follow-up CTA after 1 month revealed that all intercostal arteries planned for preservation, were patent. None of the patients developed signs of spinal cord ischaemia. 3D image fusion can be used to localise the intercostal arteries during TEVAR. This may preserve some intercostal arteries and reduce the risk of post-operative spinal cord ischaemia.

Newcastle disease virus fusion and haemagglutinin-neuraminidase proteins contribute to its macrophage host range

USDA-ARS?s Scientific Manuscript database

Newcastle disease virus (NDV) is an avian paramyxovirus that causes significant economic damage to international poultry industry. Different strains of NDV express a wide range of virulence that is primarily dependent on the amino acid sequence of the strain’s fusion (F) protein cleavage site. Two c...

Fusion Simulation Project Workshop Report

NASA Astrophysics Data System (ADS)

Kritz, Arnold; Keyes, David

2009-03-01

The mission of the Fusion Simulation Project is to develop a predictive capability for the integrated modeling of magnetically confined plasmas. This FSP report adds to the previous activities that defined an approach to integrated modeling in magnetic fusion. These previous activities included a Fusion Energy Sciences Advisory Committee panel that was charged to study integrated simulation in 2002. The report of that panel [Journal of Fusion Energy 20, 135 (2001)] recommended the prompt initiation of a Fusion Simulation Project. In 2003, the Office of Fusion Energy Sciences formed a steering committee that developed a project vision, roadmap, and governance concepts [Journal of Fusion Energy 23, 1 (2004)]. The current FSP planning effort involved 46 physicists, applied mathematicians and computer scientists, from 21 institutions, formed into four panels and a coordinating committee. These panels were constituted to consider: Status of Physics Components, Required Computational and Applied Mathematics Tools, Integration and Management of Code Components, and Project Structure and Management. The ideas, reported here, are the products of these panels, working together over several months and culminating in a 3-day workshop in May 2007.

Alternative approaches to fusion. [reactor design and reactor physics for Tokamak fusion reactors

NASA Technical Reports Server (NTRS)

Roth, R. J.

1976-01-01

The limitations of the Tokamak fusion reactor concept are discussed and various other fusion reactor concepts are considered that employ the containment of thermonuclear plasmas by magnetic fields (i.e., stellarators). Progress made in the containment of plasmas in toroidal devices is reported. Reactor design concepts are illustrated. The possibility of using fusion reactors as a power source in interplanetary space travel and electric power plants is briefly examined.

The importance of proximal fusion level selection for outcomes of multi-level lumbar posterolateral fusion.

PubMed

Nam, Woo Dong; Cho, Jae Hwan

2015-03-01

There are few studies about risk factors for poor outcomes from multi-level lumbar posterolateral fusion limited to three or four level lumbar posterolateral fusions. The purpose of this study was to analyze the outcomes of multi-level lumbar posterolateral fusion and to search for possible risk factors for poor surgical outcomes. We retrospectively analyzed 37 consecutive patients who underwent multi-level lumbar or lumbosacral posterolateral fusion with posterior instrumentation. The outcomes were deemed either 'good' or 'bad' based on clinical and radiological results. Many demographic and radiological factors were analyzed to examine potential risk factors for poor outcomes. Student t-test, Fisher exact test, and the chi-square test were used based on the nature of the variables. Multiple logistic regression analysis was used to exclude confounding factors. Twenty cases showed a good outcome (group A, 54.1%) and 17 cases showed a bad outcome (group B, 45.9%). The overall fusion rate was 70.3%. The revision procedures (group A: 1/20, 5.0%; group B: 4/17, 23.5%), proximal fusion to L2 (group A: 5/20, 25.0%; group B: 10/17, 58.8%), and severity of stenosis (group A: 12/19, 63.3%; group B: 3/11, 27.3%) were adopted as possible related factors to the outcome in univariate analysis. Multiple logistic regression analysis revealed that only the proximal fusion level (superior instrumented vertebra, SIV) was a significant risk factor. The cases in which SIV was L2 showed inferior outcomes than those in which SIV was L3. The odds ratio was 6.562 (95% confidence interval, 1.259 to 34.203). The overall outcome of multi-level lumbar or lumbosacral posterolateral fusion was not as high as we had hoped it would be. Whether the SIV was L2 or L3 was the only significant risk factor identified for poor outcomes in multi-level lumbar or lumbosacral posterolateral fusion in the current study. Thus, the authors recommend that proximal fusion levels be carefully determined when

Non-canonical role of the SNARE protein Ykt6 in autophagosome-lysosome fusion

PubMed Central

Takáts, Szabolcs; Glatz, Gábor; Szenci, Győző; Boda, Attila; Horváth, Gábor V.; Hegedűs, Krisztina; Kovács, Attila L.

2018-01-01

The autophagosomal SNARE Syntaxin17 (Syx17) forms a complex with Snap29 and Vamp7/8 to promote autophagosome-lysosome fusion via multiple interactions with the tethering complex HOPS. Here we demonstrate that, unexpectedly, one more SNARE (Ykt6) is also required for autophagosome clearance in Drosophila. We find that loss of Ykt6 leads to large-scale accumulation of autophagosomes that are unable to fuse with lysosomes to form autolysosomes. Of note, loss of Syx5, the partner of Ykt6 in ER-Golgi trafficking does not prevent autolysosome formation, pointing to a more direct role of Ykt6 in fusion. Indeed, Ykt6 localizes to lysosomes and autolysosomes, and forms a SNARE complex with Syx17 and Snap29. Interestingly, Ykt6 can be outcompeted from this SNARE complex by Vamp7, and we demonstrate that overexpression of Vamp7 rescues the fusion defect of ykt6 loss of function cells. Finally, a point mutant form with an RQ amino acid change in the zero ionic layer of Ykt6 protein that is thought to be important for fusion-competent SNARE complex assembly retains normal autophagic activity and restores full viability in mutant animals, unlike palmitoylation or farnesylation site mutant Ykt6 forms. As Ykt6 and Vamp7 are both required for autophagosome-lysosome fusion and are mutually exclusive subunits in a Syx17-Snap29 complex, these data suggest that Vamp7 is directly involved in membrane fusion and Ykt6 acts as a non-conventional, regulatory SNARE in this process. PMID:29694367

Identification of the mechanism underlying a human chimera by SNP array analysis.

PubMed

Shin, So Youn; Yoo, Han-Wook; Lee, Beom Hee; Kim, Kun Suk; Seo, Eul-Ju

2012-09-01

Human chimerism resulting from the fusion of two different zygotes is a rare phenomenon. Two mechanisms of chimerism have been hypothesized: dispermic fertilization of an oocyte and its second polar body and dispermic fertilization of two identical gametes from parthenogenetic activation, and these can be identified and discriminated using DNA polymorphism. In the present study we describe a patient with chimerism presenting as a true hermaphrodite and applied single nucleotide polymorphism array analysis to demonstrate dispermic fertilization of two identical gametes from parthenogenetic activation as the underlying mechanism at the whole chromosome level. We suggest that application of genotyping array analysis to the diagnostic process in patients with disorders of sex development will help identify more human chimera patients and increase our understanding of the underlying mechanisms. Copyright © 2012 Wiley Periodicals, Inc.

Subtalar fusion with iliac bone free flap after a recalcitrant nonunion: Report of two cases.

PubMed

Roger, Ignacio; Worden, Alicia; Panattoni, Joao; Garcia, Ignacio; Aranda, Fernando; Delgado, Paula A

2016-09-01

Fractures of the calcaneus are associated with secondary osteoarthritis of the subtalar joint. In a persistent nonunion, vascularized bone flaps offer superior biologic and mechanical properties as well as accelerates joint fusion and decreases morbidity. In this report, we present results of the use of vascularized iliac bone free flap for treating subtalar failed fusions in two patients. Two patients sustained calcaneal fractures due to foot trauma, which were initially or subsequently treated with subtalar arthrodesis. Case one developed septic subtalar nonunion during treatment and case two failed three attempts at subtalar arthrodeses. The iliac crest bone flap harvested measured 4 × 4 cm (case one) and 3 × 3 cm (case two). The flap was pedicled by the deep circumflex iliac artery, which was anastomosed to the anterior tibial artery at the recipient site. No flap donor or recipient site complications occurred. Fusion was confirmed on CT scan and weight bearing was initiated at 5-6 months. At latest follow up (1-2 years), no complications occurred. Our results show that subtalar nonunion treatment with a vascularized iliac bone flap may be feasible and such a reconstruction could be clinically successful. © 2015 Wiley Periodicals, Inc. Microsurgery 36:501-506, 2016. © 2015 Wiley Periodicals, Inc.

Site-Specific Recombination at XerC/D Sites Mediates the Formation and Resolution of Plasmid Co-integrates Carrying a blaOXA-58- and TnaphA6-Resistance Module in Acinetobacter baumannii

PubMed Central

Cameranesi, María M.; Morán-Barrio, Jorgelina; Limansky, Adriana S.; Repizo, Guillermo D.; Viale, Alejandro M.

2018-01-01

Members of the genus Acinetobacter possess distinct plasmid types which provide effective platforms for the acquisition, evolution, and dissemination of antimicrobial resistance structures. Many plasmid-borne resistance structures are bordered by short DNA sequences providing potential recognition sites for the host XerC and XerD site-specific tyrosine recombinases (XerC/D-like sites). However, whether these sites are active in recombination and how they assist the mobilization of associated resistance structures is still poorly understood. Here we characterized the plasmids carried by Acinetobacter baumannii Ab242, a multidrug-resistant clinical strain belonging to the ST104 (Oxford scheme) which produces an OXA-58 carbapenem-hydrolyzing class-D β-lactamase (CHDL). Plasmid sequencing and characterization of replication, stability, and adaptive modules revealed the presence in Ab242 of three novel plasmids lacking self-transferability functions which were designated pAb242_9, pAb242_12, and pAb242_25, respectively. Among them, only pAb242_25 was found to carry an adaptive module encompassing an ISAba825-blaOXA-58 arrangement accompanied by a TnaphA6 transposon, the whole structure conferring simultaneous resistance to carbapenems and aminoglycosides. Ab242 plasmids harbor several XerC/D-like sites, with most sites found in pAb242_25 located in the vicinity or within the adaptive module described above. Electrotransformation of susceptible A. nosocomialis cells with Ab242 plasmids followed by imipenem selection indicated that the transforming plasmid form was a co-integrate resulting from the fusion of pAb242_25 and pAb242_12. Further characterization by cloning and sequencing studies indicated that a XerC/D site in pAb242_25 and another in pAb242_12 provided the active sister pair for the inter-molecular site-specific recombination reaction mediating the fusion of these two plasmids. Moreover, the resulting co-integrate was found also to undergo intra

Degenerative lumbar scoliosis in elderly patients: dynamic stabilization without fusion versus posterior instrumented fusion.

PubMed

Di Silvestre, Mario; Lolli, Francesco; Bakaloudis, Georgios

2014-01-01

Posterolateral fusion with pedicle screw instrumentation is currently the most widely accepted technique for degenerative lumbar scoliosis in elderly patients. However, a high incidence of complications has been reported in most series. Dynamic stabilization without fusion in patients older than 60 years has not previously been compared with the use of posterior fusion in degenerative lumbar scoliosis. To compare dynamic stabilization without fusion and posterior instrumented fusion in the treatment of degenerative lumbar scoliosis in elderly patients, in terms of perioperative findings, clinical outcomes, and adverse events. A retrospective study. Fifty-seven elderly patients were included. There were 45 women (78%) and 12 men (22%) with a mean age of 68.1 years (range, 61-78 years). All patients had degenerative de novo lumbar scoliosis, associated with vertebral canal stenosis in 51 cases (89.4%) and degenerative spondylolisthesis in 24 patients (42.1%). Clinical (Oswestry Disability Index, visual analog scale, Roland-Morris Disability Questionnaire) and radiological (scoliosis and lordosis corrections) outcomes as well as incidence of complications. Patients were divided into two groups: 32 patients (dynamic group) had dynamic stabilization without fusion and 25 patients (fusion group) underwent posterior instrumented fusion. All the patients' medical records and X-rays were reviewed. Preoperative, postoperative, and follow-up questionnaires were obtained to evaluate clinical outcomes. At an average follow-up of 64 months (range, 42-90 months), clinical results improved similarly in both groups of patients. Statistically superior scoliosis and final lordosis corrections were achieved with posterior fusion (56.9% vs. 37.3% and -46.8° vs. -35.8°, respectively). However, in the dynamic group, incidence of overall complications was lower (25% vs. 44%), and fewer patients required revision surgery (6.2% vs. 16%). Furthermore, lower average values of operative

Versatile fusion source integrator AFSI for fast ion and neutron studies in fusion devices

NASA Astrophysics Data System (ADS)

Sirén, Paula; Varje, Jari; Äkäslompolo, Simppa; Asunta, Otto; Giroud, Carine; Kurki-Suonio, Taina; Weisen, Henri; JET Contributors, The

2018-01-01

ASCOT Fusion Source Integrator AFSI, an efficient tool for calculating fusion reaction rates and characterizing the fusion products, based on arbitrary reactant distributions, has been developed and is reported in this paper. Calculation of reactor-relevant D-D, D-T and D-3He fusion reactions has been implemented based on the Bosch-Hale fusion cross sections. The reactions can be calculated between arbitrary particle populations, including Maxwellian thermal particles and minority energetic particles. Reaction rate profiles, energy spectra and full 4D phase space distributions can be calculated for the non-isotropic reaction products. The code is especially suitable for integrated modelling in self-consistent plasma physics simulations as well as in the Serpent neutronics calculation chain. Validation of the model has been performed for neutron measurements at the JET tokamak and the code has been applied to predictive simulations in ITER.

Structural and kinetic analysis of the unnatural fusion protein 4-coumaroyl-CoA ligase::stilbene synthase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yechun; Yi, Hankuil; Wang, Melissa

2012-10-24

To increase the biochemical efficiency of biosynthetic systems, metabolic engineers have explored different approaches for organizing enzymes, including the generation of unnatural fusion proteins. Previous work aimed at improving the biosynthesis of resveratrol, a stilbene associated a range of health-promoting activities, in yeast used an unnatural engineered fusion protein of Arabidopsis thaliana (thale cress) 4-coumaroyl-CoA ligase (At4CL1) and Vitis vinifera (grape) stilbene synthase (VvSTS) to increase resveratrol levels 15-fold relative to yeast expressing the individual enzymes. Here we present the crystallographic and biochemical analysis of the 4CL::STS fusion protein. Determination of the X-ray crystal structure of 4CL::STS provides the firstmore » molecular view of an artificial didomain adenylation/ketosynthase fusion protein. Comparison of the steady-state kinetic properties of At4CL1, VvSTS, and 4CL::STS demonstrates that the fusion protein improves catalytic efficiency of either reaction less than 3-fold. Structural and kinetic analysis suggests that colocalization of the two enzyme active sites within 70 {angstrom} of each other provides the basis for enhanced in vivo synthesis of resveratrol.« less

Complementation between avirulent Newcastle disease virus and a fusion protein gene expressed from a retrovirus vector: requirements for membrane fusion.

PubMed Central

Morrison, T; McQuain, C; McGinnes, L

1991-01-01

The cDNA derived from the fusion gene of the virulent AV strain of Newcastle disease virus (NDV) was expressed in chicken embryo cells by using a retrovirus vector. The fusion protein expressed in this system was transported to the cell surface and was efficiently cleaved into the disulfide-linked F1-F2 form found in infectious virions. The cells expressing the fusion gene grew normally and could be passaged many times. Monolayers of these cells would plaque, in the absence of trypsin, avirulent NDV strains (strains which encode a fusion protein which is not cleaved in tissue culture). Fusion protein-expressing cells would not fuse if mixed with uninfected cells or uninfected cells expressing the hemagglutinin-neuraminidase (HN) protein. However, the fusion protein-expressing cells, if infected with avirulent strains of NDV, would fuse with uninfected cells, suggesting that fusion requires both the fusion protein and another viral protein expressed in the same cell. Fusion was also seen after transfection of the HN protein gene into fusion protein-expressing cells. Thus, the expressed fusion protein gene is capable of complementing the virus infection, providing an active cleaved fusion protein required for the spread of infection. However, the fusion protein does not mediate cell fusion unless the cell also expresses the HN protein. Fusion protein-expressing cells would not plaque influenza virus in the absence of trypsin, nor would influenza virus-infected fusion protein-expressing cells fuse with uninfected cells. Thus, the influenza virus HA protein will not substitute for the NDV HN protein in cell-to-cell fusion. Images PMID:1987376

Structural Transition and Antibody Binding of EBOV GP and ZIKV E Proteins from Pre-Fusion to Fusion-Initiation State.

PubMed

Lappala, Anna; Nishima, Wataru; Miner, Jacob; Fenimore, Paul; Fischer, Will; Hraber, Peter; Zhang, Ming; McMahon, Benjamin; Tung, Chang-Shung

2018-05-10

Membrane fusion proteins are responsible for viral entry into host cells—a crucial first step in viral infection. These proteins undergo large conformational changes from pre-fusion to fusion-initiation structures, and, despite differences in viral genomes and disease etiology, many fusion proteins are arranged as trimers. Structural information for both pre-fusion and fusion-initiation states is critical for understanding virus neutralization by the host immune system. In the case of Ebola virus glycoprotein (EBOV GP) and Zika virus envelope protein (ZIKV E), pre-fusion state structures have been identified experimentally, but only partial structures of fusion-initiation states have been described. While the fusion-initiation structure is in an energetically unfavorable state that is difficult to solve experimentally, the existing structural information combined with computational approaches enabled the modeling of fusion-initiation state structures of both proteins. These structural models provide an improved understanding of four different neutralizing antibodies in the prevention of viral host entry.

STATs and macrophage fusion.

PubMed

Miyamoto, Takeshi

2013-07-01

Macrophages play a pivotal role in host defense against multiple foreign materials such as bacteria, parasites and artificial devices. Some macrophage lineage cells, namely osteoclasts and foreign body giant cells (FBGCs), form multi-nuclear giant cells by the cell-cell fusion of mono-nuclear cells. Osteoclasts are bone-resorbing cells, and are formed in the presence of RANKL on the surface of bones, while FBGCs are formed in the presence of IL-4 or IL-13 on foreign materials such as artificial joints, catheters and parasites. Recently, fusiogenic mechanisms and the molecules required for the cell-cell fusion of these macrophage lineage cells were, at least in part, clarified. Dendritic cell specific transmembrane protein (DC-STAMP) and osteoclast stimulatory transmembrane protein (OC-STAMP), both of which comprise seven transmembrane domains, are required for both osteoclast and FBGC cell-cell fusion. STAT6 was demonstrated to be required for the cell-cell fusion of FBGCs but not osteoclasts. In this review, advances in macrophage cell-cell fusion are discussed.

Magnetized Target Fusion: Prospects for Low-Cost Fusion Energy

NASA Technical Reports Server (NTRS)

Siemon, Richard E.; Turchi, Peter J.; Barnes, Daniel C.; Degnan, James; Parks, Paul; Ryutov, Dmitri D.; Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

2001-01-01

Magnetized Target Fusion (MTF) has attracted renewed interest in recent years because it has the potential to resolve one of the major problems with conventional fusion energy research - the high cost of facilities to do experiments and in general develop practical fusion energy. The requirement for costly facilities can be traced to fundamental constraints. The Lawson condition implies large system size in the case of conventional magnetic confinement, or large heating power in the case of conventional inertial confinement. The MTF approach is to use much higher fuel density than with conventional magnetic confinement (corresponding to megabar pressures), which results in a much-reduced system size to achieve Lawson conditions. Intrinsically the system must be pulsed because the pressures exceed the strength of any known material. To facilitate heating the fuel (or "target") to thermonuclear conditions with a high-power high-intensity source of energy, magnetic fields are used to insulate the high-pressure fuel from material surroundings (thus "magnetized target"). Because of magnetic insulation, the required heating power intensity is reduced by many orders of magnitude compared to conventional inertial fusion, even with relatively poor energy confinement in the magnetic field, such as that characterized by Bohm diffusion. In this paper we show semi-quantitatively why MTF-should allow fusion energy production without costly facilities within the same generally accepted physical constraints used for conventional magnetic and inertial fusion. We also briefly discuss potential applications of this technology ranging from nuclear rockets for space propulsion to a practical commercial energy system. Finally, we report on the exploratory research underway, and the interesting physics issues that arise in the MTF regime of parameters. Experiments at Los Alamos are focused on formation of a suitable plasma target for compression, utilizing the knowledge base for compact

Stem Cells in Spinal Fusion

PubMed Central

Haudenschild, Dominik R.; Wegner, Adam M.; Klineberg, Eric O.

2017-01-01

Study Design: Review of literature. Objectives: This review of literature investigates the application of mesenchymal stem cells (MSCs) in spinal fusion, highlights potential uses in the development of bone grafts, and discusses limitations based on both preclinical and clinical models. Methods: A review of literature was conducted looking at current studies using stem cells for augmentation of spinal fusion in both animal and human models. Results: Eleven preclinical studies were found that used various animal models. Average fusion rates across studies were 59.8% for autograft and 73.7% for stem cell–based grafts. Outcomes included manual palpation and stressing of the fusion, radiography, micro–computed tomography (μCT), and histological analysis. Fifteen clinical studies, 7 prospective and 8 retrospective, were found. Fusion rates ranged from 60% to 100%, averaging 87.1% in experimental groups and 87.2% in autograft control groups. Conclusions: It appears that there is minimal clinical difference between commercially available stem cells and bone marrow aspirates indicating that MSCs may be a good choice in a patient with poor marrow quality. Overcoming morbidity and limitations of autograft for spinal fusion, remains a significant problem for spinal surgeons and further studies are needed to determine the efficacy of stem cells in augmenting spinal fusion. PMID:29238646

Outcomes of Posterolateral Fusion with and without Instrumentation and of Interbody Fusion for Isthmic Spondylolisthesis: A Prospective Study.

PubMed

Endler, Peter; Ekman, Per; Möller, Hans; Gerdhem, Paul

2017-05-03

Various methods for the treatment of isthmic spondylolisthesis are available. The aim of this study was to compare outcomes after posterolateral fusion without instrumentation, posterolateral fusion with instrumentation, and interbody fusion. The Swedish Spine Register was used to identify 765 patients who had been operated on for isthmic spondylolisthesis and had at least preoperative and 2-year outcome data; 586 of them had longer follow-up (a mean of 6.9 years). The outcome measures were a global assessment of leg and back pain, the Oswestry Disability Index (ODI), the EuroQol-5 Dimensions (EQ-5D) Questionnaire, the Short Form-36 (SF-36), a visual analog scale (VAS) for back and leg pain, and satisfaction with treatment. Data on additional lumbar spine surgery was searched for in the register, with the mean duration of follow-up for this variable being 10.6 years after the index procedure. Statistical analyses were performed with analysis of covariance or competing-risks proportional hazards regression, adjusted for baseline differences in the studied variables, smoking, employment status, and level of fusion. Posterolateral fusion without instrumentation was performed in 102 patients; posterolateral fusion with instrumentation, in 452; and interbody fusion, in 211. At 1 year, improvement was reported in the global assessment for back pain by 54% of the patients who had posterolateral fusion without instrumentation, 68% of those treated with posterolateral fusion with instrumentation, and 70% of those treated with interbody fusion (p = 0.009). The VAS for back pain and reported satisfaction with treatment showed similar patterns (p = 0.003 and p = 0.017, respectively), whereas other outcomes did not differ among the treatment groups at 1 year. At 2 years, the global assessment for back pain indicated improvement in 57% of the patients who had undergone posterolateral fusion without instrumentation, 70% of those who had posterolateral fusion with instrumentation

Enfuvirtide (T20)-Based Lipopeptide Is a Potent HIV-1 Cell Fusion Inhibitor: Implications for Viral Entry and Inhibition.

PubMed

Ding, Xiaohui; Zhang, Xiujuan; Chong, Huihui; Zhu, Yuanmei; Wei, Huamian; Wu, Xiyuan; He, Jinsheng; Wang, Xinquan; He, Yuxian

2017-09-15

The peptide drug enfuvirtide (T20) is the only viral fusion inhibitor used in combination therapy for HIV-1 infection, but it has relatively low antiviral activity and easily induces drug resistance. Emerging studies demonstrate that lipopeptide-based fusion inhibitors, such as LP-11 and LP-19, which mainly target the gp41 pocket site, have greatly improved antiviral potency and in vivo stability. In this study, we focused on developing a T20-based lipopeptide inhibitor that lacks pocket-binding sequence and targets a different site. First, the C-terminal tryptophan-rich motif (TRM) of T20 was verified to be essential for its target binding and inhibition; then, a novel lipopeptide, termed LP-40, was created by replacing the TRM with a fatty acid group. LP-40 showed markedly enhanced binding affinity for the target site and dramatically increased inhibitory activity on HIV-1 membrane fusion, entry, and infection. Unlike LP-11 and LP-19, which required a flexible linker between the peptide sequence and the lipid moiety, addition of a linker to LP-40 sharply reduced its potency, implying different binding modes with the extended N-terminal helices of gp41. Also, interestingly, LP-40 showed more potent activity than LP-11 in inhibiting HIV-1 Env-mediated cell-cell fusion while it was less active than LP-11 in inhibiting pseudovirus entry, and the two inhibitors displayed synergistic antiviral effects. The crystal structure of LP-40 in complex with a target peptide revealed their key binding residues and motifs. Combined, our studies have not only provided a potent HIV-1 fusion inhibitor, but also revealed new insights into the mechanisms of viral inhibition. IMPORTANCE T20 is the only membrane fusion inhibitor available for treatment of viral infection; however, T20 requires high doses and has a low genetic barrier for resistance, and its inhibitory mechanism and structural basis remain unclear. Here, we report the design of LP-40, a T20-based lipopeptide inhibitor

Induction of cell-cell fusion by ectromelia virus is not inhibited by its fusion inhibitory complex.