Sample records for kill invading microorganisms

  1. Killing of microorganisms by pulsed electric fields

    Microsoft Academic Search

    T. Grahl; H. Märkl

    1996-01-01

    Lethal effects of pulsed electric fields (PEF) on suspensions of various bacteria, yeast, and spores in buffer solutions and\\u000a liquid foodstuffs were examined. Living-cell counts of vegetative cell types were reduced by PEF treatment by up to more than\\u000a four orders of magnitude (> 99.99%). On the other hand, endoand ascospores were not inactivated or killed to any great extent.

  2. Killing Microorganisms with the One Atmosphere Uniform Glow Discharge Plasma

    NASA Astrophysics Data System (ADS)

    South, Suzanne; Kelly-Wintenberg, Kimberly; Montie, T. C.; Reece Roth, J.; Sherman, Daniel; Morrison, Jim; Chen, Zhiyu; Karakaya, Fuat

    2000-10-01

    There is an urgent need for the development of new technologies for sterilization and decontamination in the fields of healthcare and industrial and food processing that are safe, cost-effective, broad-spectrum, and not deleterious to samples. One technology that meets these criteria is the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP). The OAUGDP operates in air and produces uniform plasma without filamentary discharges at room temperature, making this technology advantageous for sterilization of heat sensitive materials. The OAUGDP operates in a frequency band determined by the ion trapping mechanisms provided that, for air, the electric field is above 8.5kV/cm. The OAUGDP efficiently generates plasma reactive oxygen species (ROS) including atomic oxygen and oxygen free radicals without the requirement of a vacuum system. We have demonstrated the efficacy of the OAUGDP in killing microorganisms including bacteria, yeast, viruses, and spores in seconds to minutes on a variety of surfaces such as glass, films and fabrics, stainless steel, paper, and agar.

  3. Plankton Microorganisms Coinciding with Two Consecutive Mass Fish Kills in a Newly Reconstructed Lake

    PubMed Central

    Oikonomou, Andreas; Katsiapi, Matina; Karayanni, Hera; Moustaka-Gouni, Maria; Kormas, Konstantinos Ar.

    2012-01-01

    Lake Karla, Greece, was dried up in 1962 and its refilling started in 2009. We examined the Cyanobacteria and unicellular eukaryotes found during two fish kill incidents, in March and April 2010, in order to detect possible causative agents. Both microscopic and molecular (16S/18S rRNA gene diversity) identification were applied. Potentially toxic Cyanobacteria included representatives of the Planktothrix and Anabaena groups. Known toxic eukaryotes or parasites related to fish kill events were Prymnesium parvum and Pfiesteria cf. piscicida, the latter being reported in an inland lake for the second time. Other potentially harmful microorganisms, for fish and other aquatic life, included representatives of Fungi, Mesomycetozoa, Alveolata, and Heterokontophyta (stramenopiles). In addition, Euglenophyta, Chlorophyta, and diatoms were represented by species indicative of hypertrophic conditions. The pioneers of L. Karla's plankton during the first months of its water refilling process included species that could cause the two observed fish kill events. PMID:22654619

  4. INVADERS Database

    NSDL National Science Digital Library

    Based at the University of Montana and directed by Dr. Peter Rice, the INVADERS Database is "a comprehensive database of exotic plant names and weed distribution records for five states in the northwestern United States." Designed for use by land management and weed regulatory agencies, INVADERS uses a query interface (plant name or location) to sort and display information. Data are updated regularly so as to increase the chance of detecting and halting the rapid spread of alien weeds. Highlights of the site include the noxious weed listings for all US states and six Canadian provinces, historic distribution records against which to compare current plant distributions, and summary statistics such as the number of invasive species detected per state or a summary of the 120 year invasion, among others. The INVADERS database will prove both interesting and useful to managers and academics, alike.

  5. Alien invaders.

    PubMed

    Gross, Michael

    2012-10-01

    Thousands of species have invaded new territories in recent decades, often aided by global trade and man-made habitat change. While many remain harmless, some may cause serious damage. Therefore, we need improvements in surveillance and in our understanding of which factors make a successful invasion possible. PMID:23227487

  6. Silent Invaders

    NSDL National Science Digital Library

    David LaHart

    Silent Invaders introduces the problem of invasive species and provides information on control activities. The videos explain how invasive species get into the United States, why some do so well here, and how we can keep invasive species out. There is an interactive section where the user tries to eliminate musk thistle by applying a combination of biological, fire, chemical and mechanical controls. Other featured species include cheatgrass, tamarisk, woolly adelgid, zebra mussel, and fire ants. The field guide contains a list of invasive plant and animal species as well as photographs and movies. The instructor guide is a weed science primer for teachers.

  7. Nab the Aquatic Invader!

    NSDL National Science Digital Library

    In this activity, younger students assume the roles of detectives investigating the ten "most wanted" invasive species. They examine background information on these species and learn about how they came to be invaders, how they spread, some environmental and economic impacts, and some solutions for controlling them. When they think they have enough information to "book" an invasive species, they click on the "Book 'em" file and answer questions about each one.

  8. Myeloperoxidase: a front-line defender against phagocytosed microorganisms

    PubMed Central

    Klebanoff, Seymour J.; Kettle, Anthony J.; Rosen, Henry; Winterbourn, Christine C.; Nauseef, William M.

    2013-01-01

    Successful immune defense requires integration of multiple effector systems to match the diverse virulence properties that members of the microbial world might express as they initiate and promote infection. Human neutrophils—the first cellular responders to invading microbes—exert most of their antimicrobial activity in phagosomes, specialized membrane-bound intracellular compartments formed by ingestion of microorganisms. The toxins generated de novo by the phagocyte NADPH oxidase and delivered by fusion of neutrophil granules with nascent phagosomes create conditions that kill and degrade ingested microbes. Antimicrobial activity reflects multiple and complex synergies among the phagosomal contents, and optimal action relies on oxidants generated in the presence of MPO. The absence of life-threatening infectious complications in individuals with MPO deficiency is frequently offered as evidence that the MPO oxidant system is ancillary rather than essential for neutrophil-mediated antimicrobial activity. However, that argument fails to consider observations from humans and KO mice that demonstrate that microbial killing by MPO-deficient cells is less efficient than that of normal neutrophils. We present evidence in support of MPO as a major arm of oxidative killing by neutrophils and propose that the essential contribution of MPO to normal innate host defense is manifest only when exposure to pathogens overwhelms the capacity of other host defense mechanisms. PMID:23066164

  9. Original article Prevalence of microorganisms in dead mink kits

    E-print Network

    Paris-Sud XI, Université de

    Original article Prevalence of microorganisms in dead mink kits from Aleutian, liver, heart) taken from 81 dead newborn mink originating from Aleutian disease (AD) infected and AD of these microorganisms as specific pathogens or secondary invaders remains controversial. mink I bacteriology I Aleutian

  10. Killing Range

    PubMed Central

    Asal, Victor; Rethemeyer, R. Karl; Horgan, John

    2015-01-01

    This paper presents an analysis of the Provisional Irish Republican Army's (PIRA) brigade level behavior during the Northern Ireland Conflict (1970-1998) and identifies the organizational factors that impact a brigade's lethality as measured via terrorist attacks. Key independent variables include levels of technical expertise, cadre age, counter-terrorism policies experienced, brigade size, and IED components and delivery methods. We find that technical expertise within a brigade allows for careful IED usage, which significantly minimizes civilian casualties (a specific strategic goal of PIRA) while increasing the ability to kill more high value targets with IEDs. Lethal counter-terrorism events also significantly affect a brigade's likelihood of killing both civilians and high-value targets but in different ways. Killing PIRA members significantly decreases IED fatalities but also significantly decreases the possibility of zero civilian IED-related deaths in a given year. Killing innocent Catholics in a Brigade's county significantly increases total and civilian IED fatalities. Together the results suggest the necessity to analyze dynamic situational variables that impact terrorist group behavior at the sub-unit level. PMID:25838603

  11. Killing Tensors and Conformal Killing Tensors from Conformal Killing Vectors

    E-print Network

    Raffaele Rani; S. Brian Edgar; Alan Barnes

    2003-03-12

    Koutras has proposed some methods to construct reducible proper conformal Killing tensors and Killing tensors (which are, in general, irreducible) when a pair of orthogonal conformal Killing vectors exist in a given space. We give the completely general result demonstrating that this severe restriction of orthogonality is unnecessary. In addition we correct and extend some results concerning Killing tensors constructed from a single conformal Killing vector. A number of examples demonstrate how it is possible to construct a much larger class of reducible proper conformal Killing tensors and Killing tensors than permitted by the Koutras algorithms. In particular, by showing that all conformal Killing tensors are reducible in conformally flat spaces, we have a method of constructing all conformal Killing tensors (including all the Killing tensors which will in general be irreducible) of conformally flat spaces using their conformal Killing vectors.

  12. 2005. The Journal of Arachnology 33:16 BEHAVIOR OF WEB-INVADING SPIDERS ARGYRODES

    E-print Network

    Kerr, Alexander M.

    1 2005. The Journal of Arachnology 33:1­6 BEHAVIOR OF WEB-INVADING SPIDERS ARGYRODES ARGENTATUS, University of Guam, Mangilao GU 96923 USA ABSTRACT. Most Argyrodes live in the webs of other spiders, stealing food from the host, scavenging small prey from the web or killing and eating the host. I observed

  13. Killing Tensors from Conformal Killing Vectors

    E-print Network

    A. Barnes; S. B. Edgar; R. Rani

    2002-12-03

    Some years ago Koutras presented a method of constructing a conformal Killing tensor from a pair of orthogonal conformal Killing vectors. When the vector associated with the conformal Killing tensor is a gradient, a Killing tensor (in general irreducible) can then be constructed. In this paper it is shown that the severe restriction of orthogonality is unnecessary and thus it is possible that many more Killing tensors can be constructed in this way. We also extend, and in one case correct, some results on Killing tensors constructed from a single conformal Killing vector. Weir's result that, for flat space, there are 84 independent conformal Killing tensors, all of which are reducible, is extended to conformally flat spacetimes. In conformally flat spacetimes it is thus possible to construct all the conformal Killing tensors and in particular all the Killing tensors (which in general will not be reducible) from conformal Killing vectors.

  14. Progress in invasion biology: predicting invaders

    Microsoft Academic Search

    Cynthia S. Kolar; David M. Lodge

    2001-01-01

    Predicting which species are probable invaders has been a long-standing goal of ecologists, but only recently have quantitative methods been used to achieve such a goal. Although restricted to few taxa, these studies reveal clear relationships between the characteristics of releases and the species involved, and the successful establishment and spread of invaders. For example, the probability of bird establishment

  15. Why do Invasive Species Successfully Establish & Invade?

    E-print Network

    Schweik, Charles M.

    Why do Invasive Species Successfully Establish & Invade? #12;Many are introduced, few become invasive #12;Hypotheses about why invaders succeed: 1. Invasive species have traits that favor establishment and spread 2. Invasive species are released from enemies 3. Invasive species exploit empty niches

  16. Why do Invasive Species Successfully Establish & Invade?

    E-print Network

    Schweik, Charles M.

    Why do Invasive Species Successfully Establish & Invade? #12;Hypotheses about why invaders succeed: 1. Invasive species have traits that favor establishment and spread 2. Invasive species are released from enemies 3. Invasive species exploit empty niches 4. Invasive species are favored by anthropogenic

  17. [Action of physical agents on microorganisms].

    PubMed

    Strus, M

    1997-01-01

    Among numerous physical agents exerting their deleterious effect on microorganisms only a few have been applied to sterilisation or disinfection used for medical purposes. Temperature is the most important agent, which from one side in a very wide range enables supporting of metabolic processes of psycho-, mezo- and thermophilic microorganisms, but beyond these limits causes their death. High temperature induces at first damage of cytoplasmic membrane and then denaturation of RNA leading to death. On the other hand, a low temperature slowly decreasing below 0 degree C induces crystallisation of water in cells and destruction of cytoplasmic structures. Ultraviolet radiation causes mutations resulting in stopping of DNA replication in all forms of the microorganisms. The same way of the lethal activity is exerted by ionising radiation. Its kinetic energy induces mutations affecting not single bases but also whole operons making gene expression impossible. Gaseous plasma is a new physical agent applied recently to sterilisation. High frequency energy initiates generation of the plasma from hydrogen peroxide vapours in a high vacuum and creates reactive species particles from the vapours that collide and kill microorganisms. On the other hand, application of ultrasound radiation to killing of microorganisms needs for further studies because of a high variability depending upon used frequency and energy. It is not known, for example, if destruction of microorganisms by ultrasounds is related to a phenomenon of cavitation or thermal energy. Nevertheless, even a range of frequency and energy used in commercial microwave ovens kills vegetative cells of coliform rods in about 15 minutes. PMID:9432703

  18. Effect of microwaves on microorganisms in foods

    SciTech Connect

    Fung, D.Y.C.; Cunningham, F.E.

    1980-08-01

    The microbial safety of foods cooked in microwave ovens was investigated. The mechanisms of microwave destruction of microorganisms were examined. Effects of time and temperature on microorganisms in different food systems were described. Studies showed that: microwave heating of food is more ''''food dependent'' than conventional heating; recommended microwave treatment time for some foods may not destroy high levels of bacteria; use of microwaves in combination with conventional heating methods results in more uniform heating of foods and destruction of bacteria; and microwaves exert different killing effects on individual bacterial species. (78 references, 2 tables)

  19. Killing Tensors and Symmetries

    E-print Network

    David Garfinkle; E. N. Glass

    2010-03-10

    A new method is presented for finding Killing tensors in spacetimes with symmetries. The method is used to find all the Killing tensors of Melvin's magnetic universe and the Schwarzschild vacuum. We show that they are all trivial. The method requires less computation than solving the full Killing tensor equations directly, and it can be used even when the spacetime is not algebraically special.

  20. Planning a dynamic kill

    SciTech Connect

    Abel, L.W. [Abel Engineering, Houston, TX (United States)

    1996-05-01

    This article discusses the methodology, design philosophy, and guidelines for planning a dynamic-kill operation for a wild well. The topics covered are two methods of computer analysis for designing dynamic-kill requirements, the design process, determining the pumping spread, and the pitfalls that a designer faces in planning a dynamic kill.

  1. Appendix carcinoma invading the urinary bladder.

    PubMed

    Dahms, S E; Hohenfellner, M; Eggersmann, C; Lampel, A; Golz, R; Thüroff, J W

    1997-01-01

    We report a case of an appendix carcinoma invading the urinary bladder. In contrast to other bowel tumors invading the bladder, history and symptoms were consistent with a primary bladder tumor. This is due to the unique anatomical position of the appendix where the tumor did not hinder passage of bowel contents or cause melena. Findings on physical examination as well as diagnostic imaging and transurethral resection were inconclusive. Consideration of local progression of an appendix carcinoma is an important differential diagnosis. In contrast to other vesical or extravesical T4 tumors, the appendix carcinoma offers a good chance for resection en bloc by right-sided hemicolectomy and partial cystectomy. PMID:9096277

  2. New Health Potentials of Orally Consumed Probiotic Microorganisms

    Microsoft Academic Search

    Vivekananda Mandal; Narayan C. Mandal

    \\u000a The microorganism and their live formulations upon consumption contribute to intestinal microbial balance are known as probiotics.\\u000a They generally live in our gut mucosal layer and also in some other body parts like mouth, vagina and offer a number of health\\u000a benefits to the host. They fight with the invading pathogens by producing a number of active principles like bacteriocins

  3. Irreducible Killing Tensors from Third Rank Killing-Yano Tensors

    E-print Network

    Florian Catalin Popa; Ovidiu Tintareanu-Mircea

    2006-12-30

    We investigate higher rank Killing-Yano tensors showing that third rank Killing-Yano tensors are not always trivial objects being possible to construct irreducible Killing tensors from them. We give as an example the Kimura IIC metric were from two rank Killing-Yano tensors we obtain a reducible Killing tensor and from third rank Killing-Yano tensors we obtain three Killing tensors, one reducible and two irreducible.

  4. Ion-kill dosimetry

    NASA Technical Reports Server (NTRS)

    Katz, R.; Cucinotta, F. A.; Fromm, M.; Chambaudet, A.

    2001-01-01

    Unanticipated late effects in neutron and heavy ion therapy, not attributable to overdose, imply a qualitative difference between low and high LET therapy. We identify that difference as 'ion kill', associated with the spectrum of z/beta in the radiation field, whose measurement we label 'ion-kill dosimetry'.

  5. BB Guns Can Kill

    MedlinePLUS

    U.S. CONSUMER PRODUCT SAFETY COMMISSION • (800) 638-2772 • www.cpsc.gov • www.SaferProducts.gov BB Guns Can Kill BB guns can kill ... second, can increase this risk. The U.S. Consumer Product Safety Commission has reports of about 4 deaths per ...

  6. Cloning, killing, and identity.

    PubMed Central

    McMahan, J

    1999-01-01

    One potentially valuable use of cloning is to provide a source of tissues or organs for transplantation. The most important objection to this use of cloning is that a human clone would be the sort of entity that it would be seriously wrong to kill. I argue that entities of the sort that you and I essentially are do not begin to exist until around the seventh month of fetal gestation. Therefore to kill a clone prior to that would not be to kill someone like you or me but would be only to prevent one of us from existing. And even after one of us begins to exist, the objections to killing it remain comparatively weak until its psychological capacities reach a certain level of maturation. These claims support the permissibility of killing a clone during the early stages of its development in order to use its organs for transplantation. PMID:10226909

  7. Microorganisms in honey

    Microsoft Academic Search

    Jill A Snowdon; Dean O Cliver

    1996-01-01

    Knowledge of the moisture and temperature conditions influencing growth of microorganisms in honey has long been used to control the spoilage of honey. However, the need for additional microbiological data on honey will increase as new technologies for, and uses of honey develop. Microorganisms in honey may influence quality or safety. Due to the natural properties of honey and control

  8. Cercopagis Pengoi Invades the Great Lakes

    NSDL National Science Digital Library

    Barbiero, Rick.

    1998-01-01

    The Environmental Protection Agency (EPA)'s Great Lakes National Program Office provides this research information page on the recent invasion of the exotic crustacean, Cercopagis pengoi, into the Great Lakes. Cercopagis, a predatory cladoceran, is similar to Bythotrephes cederstroemi, another recent Great Lakes invader; both species occur in freshwater and brackish environments. The site provides background information, images (including figures showing distribution and abundance), links, and selected references regarding this exotic species.

  9. Ecology. Plant invader may use chemical weapons.

    PubMed

    Jensen, M N

    2000-10-20

    On page 521, plant ecologists offer a novel explanation for the success of invasive plants. By comparing how one species of knapweed, Centaurea diffusa, behaves with its natural neighbors and with foreign plant species that evolved separately, they found that the invader apparently gains an edges in its adopted home not only by ditching its herbivores but by wielding weaponry: chemicals exuded from its roots that hamper its new neighbors' growth. PMID:11183749

  10. HOW NEUTROPHILS KILL MICROBES

    Microsoft Academic Search

    Anthony W. Segal

    2005-01-01

    ? Abstract Neutrophils provide the first line of defense of the innate immune,sys- tem by phagocytosing, killing, and digesting bacteria and fungi. Killing was previously believed to be accomplished,by oxygen,free radicals and other reactive oxygen,species generated by the NADPH oxidase, and by oxidized halides produced by myeloperoxi- dase. We now,know,this is incorrect. The oxidase pumps,electrons into the phagocytic vacuole, thereby

  11. Male-killing bacteria in insects: mechanisms, incidence, and implications.

    PubMed Central

    Hurst, G. D.; Jiggins, F. M.

    2000-01-01

    Bacteria that are vertically transmitted through female hosts and kill male hosts that inherit them were first recorded in insects during the 1950s. Recent studies have shown these "male-killers" to be diverse and have led to a reappraisal of the biology of many groups of bacteria. Rickettsia, for instance, have been regarded as human pathogens transmitted by arthropods. The finding of a male-killing Rickettsia obligately associated with an insect suggests that the genus' members may be primarily associated with arthropods and are only sometimes pathogens of vertebrates. We examined both how killing of male hosts affects the dynamics of inherited bacteria and how male-killing bacteria affect their host populations. Finally, we assessed the potential use of these microorganisms in the control of insect populations. PMID:10905965

  12. Chinese Tallow: Invading the Southeastern Coastal Plain

    USGS Publications Warehouse

    U.S. Geological Survey

    2000-01-01

    Chinese tallow is an ornamental tree with colorful autumn foliage that can survive full sunlight and shade, flooding, drought, and in some cases fire. To horticulturists this kind of tree sounds like a dream, but to ecologists, land managers, and land owners this kind of tree can be a nightmare, especially when it invades an area and takes over native vegetation. Chinese tallow (Triadica sebifera), a nonnative tree from China, is currently transforming the southeastern Coastal Plain. Over the last 30 years, Chinese tallow has become a common tree in old fields and bottomland swamps of coastal Louisiana. Several studies at the U.S. Geological Survey's National Wetlands Research Center (NWRC), Lafayette, Louisiana, are aimed at understanding the factors that contribute to Chinese tallow growth, spread, and management. When tallow invades, it eventually monopolizes an area, creating a forest without native animal or plant species. This tree exhibits classic traits of most nonnative invaders: it is attractive so people want to distribute it, it has incredible resiliency, it grows quickly and in a variety of soils, and it is resistant to pests. In the coastal prairie of Louisiana and Texas, Chinese tallow can grow up to 30 feet and shade out native sun-loving prairie species. The disappearing of prairie species is troublesome because less than 1% of original coastal prairie remains, and in Louisiana, less than 500 of the original 2.2 million acres still exist. Tallow reproduces and grows quickly and can cause large-scale ecosystem modification (fig. 1). For example, when it completely replaces native vegetation, it has a negative effect on birds by degrading the habitat. Besides shading out grasses that cattle like to eat, it can also be potentially harmful to humans and animals because of its berries (fig. 2) and plant sap that contain toxins. There is some concern its leaves may shed toxins that change the soil chemistry and make it difficult for other plants to grow.

  13. 33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117...801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a...bridges across Newtown Creek, Dutch Kills, English Kills, and their tributaries:...

  14. Microorganism identification technique

    SciTech Connect

    Sillman, R. E.

    1985-07-02

    An identification technique for micro-organisms in which a dilute solution of a culture medium containing an unknown micro-organism has added thereto an emissive agent such as a radioactive amino acid to produce a mix of emissive products that depends on the metabolic mechanism of the micro-organism. After a predetermined incubation period, the reaction is arrested and the solution layered onto a gel plate where it is subjected to electrophoresis. The plate is then autoradiographed by exposing the gel to a sensitive photographic film for a period sufficient to produce thereon a characteristic band pattern functioning as an identifier for the micro-organism. Identification may be effected by comparing the identifier for the unknown with a collection of identifiers for known micro-organisms to find a match with one of these known identifiers. The comparison is preferably carried out by scanning the unknown identifier to produce a signal which is compared with signals representing known identifiers stored in a computer which, when a match is found, yields identification data. Alternatively, the emissive products, after separation, may be detected by direct scanning to provide an identifier signal for computer processing.

  15. Redshifts and Killing Vectors

    E-print Network

    Alex Harvey; Engelbert L. Schucking; Eugene J. Surowitz

    2005-08-31

    Courses in introductory special and general relativity have increasingly become part of the curriculum for upper-level undergraduate physics majors and master's degree candidates. One of the topics rarely discussed is symmetry, particularly in the theory of general relativity. The principal tool for its study is the Killing vector. We provide an elementary introduction to the concept of a Killing vector field, its properties, and as an example of its utility apply these ideas to the rigorous determination of gravitational and cosmological redshifts.

  16. Micro-Organ Devices

    NASA Technical Reports Server (NTRS)

    Gonda, Steven R.; Leslie, Julia; Chang, Robert C.; Starly, Binil; Sun, Wei; Culbertson, Christopher; Holtorf, Heidi

    2009-01-01

    Micro-organ devices (MODs) are being developed to satisfy an emerging need for small, lightweight, reproducible, biological-experimentati on apparatuses that are amenable to automated operation and that imp ose minimal demands for resources (principally, power and fluids). I n simplest terms, a MOD is a microfluidic device containing a variety of microstructures and assemblies of cells, all designed to mimic a complex in vivo microenvironment by replicating one or more in vivo micro-organ structures, the architectures and composition of the extr acellular matrices in the organs of interest, and the in vivo fluid flows. In addition to microscopic flow channels, a MOD contains one or more micro-organ wells containing cells residing in microscopic e xtracellular matrices and/or scaffolds, the shapes and compositions o f which enable replication of the corresponding in vivo cell assembl ies and flows.

  17. Microorganisms and microbial toxins.

    PubMed

    Reid, D S; Harris, L J

    1999-01-01

    The primary concern in food safety issues focuses on microorganisms and microbial toxins. Effective food preservation requires that the growth and proliferation of hazardous microorganisms be well controlled, and that the presence of significant quantities of microbial toxins in foods be prevented. The traditional effective preservation methodologies, such as canning, are being supplemented by new technologies which are less destructive of the food qualities. New strategies are therefore needed to prevent the transmission of microbial contamination or to prevent the formation of microbial toxins which remain in food. This paper discusses the role of modern processing methodologies in helping protect consumers from hazards of microbial origin. PMID:10335366

  18. The Fish Kill Mystery

    NSDL National Science Digital Library

    Erica F. Kosal

    2004-02-01

    In this case, students speculate on what may have caused a major fish kill in an estuary in North Carolina. In the process they explore how land runoff and excess nutrients affect aquatic communities and learn about the complex life cycle of the dinoflagellate Pfiesteria.

  19. Killing vectors and anisotropy

    E-print Network

    J. P. Krisch; E. N. Glass

    2009-08-03

    We consider an action that can generate fluids with three unequal stresses for metrics with a spacelike Killing vector. The parameters in the action are directly related to the stress anisotropies. The field equations following from the action are applied to an anisotropic cosmological expansion and an extension of the Gott-Hiscock cosmic string.

  20. Killing vectors and anisotropy

    SciTech Connect

    Krisch, J. P.; Glass, E. N. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2009-08-15

    We consider an action that can generate fluids with three unequal stresses for metrics with a spacelike Killing vector. The parameters in the action are directly related to the stress anisotropies. The field equations following from the action are applied to an anisotropic cosmological expansion and an extension of the Gott-Hiscock cosmic string.

  1. How killer cells kill.

    PubMed

    Young, J D; Cohn, Z A

    1988-01-01

    Killer lymphocytes, the commandos of the immune system, attack tumor cells and cells infected by viruses. They kill by secreting protein molecules that link to form pores in target cells; the cells promptly leak to death. Study of the process may make it possible to improve the killers' efficiency in fighting cancer and such viral infections as AIDS. PMID:3051347

  2. Amine Oxidases of Microorganisms

    Microsoft Academic Search

    O. V. Yagodina; E. B. Nikol'skaya; A. E. Khovanskikh; B. N. Kormilitsyn

    2002-01-01

    The review of works on amine oxidases of microorganisms is presented. Preparation, physical-chemical and kinetic properties of amine oxidases from archaebacteria Methanosarcina barkery, group of methane-producing archaebacteria, eubacteria, Sarcina lutea, Micrococcus rubens, M. lutea, representatives of Enterobacteriaceae family, such as Klebsiella and Escherichia, are considered. Besides, the amine oxidases obtained from mycelium of fungus Aspergillus niger are described. The works

  3. Microorganisms and Man.

    ERIC Educational Resources Information Center

    Noble, W. C.

    1983-01-01

    Provides information to update Institute of Biology's Studies in Biology No. 111, "Microorganisms and Man," by W. C. Noble and Jay Naidoo (Edward Arnold, 1979). Topics include: (1) food poisoning; (2) airborn infections in man; (3) infection in animals and plants; and (4) biodegradation and biosynthesis. (JN)

  4. Comparing Sizes of Microorganisms

    NSDL National Science Digital Library

    Nancy P. Moreno

    2008-01-01

    In this activity related to microbes, learners create scale models of microorganisms and compare relative sizes of common bacteria, viruses, fungi and protozoa using metric measures: meters, centimeters and micrometers. Learners will discover that microbes come in many different sizes and shapes, and frequently are measured in micrometers. This lesson guide includes background information and handouts.

  5. Mechanism of Immunologically Specific Killing of Tumour Cells by Macrophages

    Microsoft Academic Search

    R. Evans; P. Alexander

    1972-01-01

    THE increase in anti-microbial activity of macrophages which occurs in animals that have been infected with living microorganisms is frequently non-specific1. In contrast, the anti-tumour activity of macrophages from immunized animals has been demonstrated in vitro to be immunologically specific2,3. The experiments to be described may throw light on this paradox. They show that the killing of tumour cells by

  6. Inefficient Complement System Clearance of Trypanosoma cruzi Metacyclic Trypomastigotes Enables Resistant Strains to Invade Eukaryotic Cells

    PubMed Central

    Cestari, Igor; Ramirez, Marcel I.

    2010-01-01

    The complement system is the main arm of the vertebrate innate immune system against pathogen infection. For the protozoan Trypanosoma cruzi, the causative agent of Chagas disease, subverting the complement system and invading the host cells is crucial to succeed in infection. However, little attention has focused on whether the complement system can effectively control T. cruzi infection. To address this question, we decided to analyse: 1) which complement pathways are activated by T. cruzi using strains isolated from different hosts, 2) the capacity of these strains to resist the complement-mediated killing at nearly physiological conditions, and 3) whether the complement system could limit or control T. cruzi invasion of eukaryotic cells. The complement activating molecules C1q, C3, mannan-binding lectin and ficolins bound to all strains analysed; however, C3b and C4b deposition assays revealed that T. cruzi activates mainly the lectin and alternative complement pathways in non-immune human serum. Strikingly, we detected that metacyclic trypomastigotes of some T. cruzi strains were highly susceptible to complement-mediated killing in non-immune serum, while other strains were resistant. Furthermore, the rate of parasite invasion in eukaryotic cells was decreased by non-immune serum. Altogether, these results establish that the complement system recognizes T. cruzi metacyclic trypomastigotes, resulting in killing of susceptible strains. The complement system, therefore, acts as a physiological barrier which resistant strains have to evade for successful host infection. PMID:20300530

  7. Inefficient complement system clearance of Trypanosoma cruzi metacyclic trypomastigotes enables resistant strains to invade eukaryotic cells.

    PubMed

    Cestari, Igor; Ramirez, Marcel I

    2010-01-01

    The complement system is the main arm of the vertebrate innate immune system against pathogen infection. For the protozoan Trypanosoma cruzi, the causative agent of Chagas disease, subverting the complement system and invading the host cells is crucial to succeed in infection. However, little attention has focused on whether the complement system can effectively control T. cruzi infection. To address this question, we decided to analyse: 1) which complement pathways are activated by T. cruzi using strains isolated from different hosts, 2) the capacity of these strains to resist the complement-mediated killing at nearly physiological conditions, and 3) whether the complement system could limit or control T. cruzi invasion of eukaryotic cells. The complement activating molecules C1q, C3, mannan-binding lectin and ficolins bound to all strains analysed; however, C3b and C4b deposition assays revealed that T. cruzi activates mainly the lectin and alternative complement pathways in non-immune human serum. Strikingly, we detected that metacyclic trypomastigotes of some T. cruzi strains were highly susceptible to complement-mediated killing in non-immune serum, while other strains were resistant. Furthermore, the rate of parasite invasion in eukaryotic cells was decreased by non-immune serum. Altogether, these results establish that the complement system recognizes T. cruzi metacyclic trypomastigotes, resulting in killing of susceptible strains. The complement system, therefore, acts as a physiological barrier which resistant strains have to evade for successful host infection. PMID:20300530

  8. Interpopulation variation in allelopathic traits informs restoration of invaded landscapes

    PubMed Central

    Lankau, Richard A

    2012-01-01

    Invasive species can show substantial genetic variation in ecologically important traits, across ranges as well within the introduced range. If these traits affect competition with native species, then management may benefit from considering the genetic landscape of the invader. Across their introduced range, Alliaria petiolata populations vary in their investment in allelopathic traits according to invasion history, which could lead to gradients of impact on native species. Red oak (Quercus rubra) seedlings were transplanted into eight A. petiolata-invaded sites that varied in their invasion history and allelochemical concentrations. At each site, an invader removal treatment was crossed with experimental inoculations of native soil biota, to test whether the benefits of these restoration actions differed across invader populations. Q. rubra seedlings grew faster in invader populations with a longer invasion history and lower allelochemical concentrations. Invader removal and soil inoculation interacted to determine seedling growth, with the benefits of soil inoculation increasing in younger and more highly allelopathic invader populations. A greenhouse experiment using soils collected from experimentally inoculated field plots found similar patterns. These results suggest that the impact of this invader varies across landscapes and that knowledge of this variation could improve the efficacy and efficiency of restoration activities. PMID:25568047

  9. Action potentials reliably invade axonal arbors of rat neocortical neurons

    E-print Network

    Tank, David

    Action potentials reliably invade axonal arbors of rat neocortical neurons Charles L. Cox axonal arboriza- tions that make thousands of synapses. Action potentials can invade these arbors targets. Thus, the regulation of action potential invasion in axonal branches might shape the spread

  10. Donor and recipient regions: The biogeography of macrobenthic invaders

    EPA Science Inventory

    Aquatic invaders are a major threat to ecological integrity and biodiversity of marine, estuarine, and freshwater ecosystems around the world. These invaders have been successful in passing through four discrete phases in their invasion of a new environment: (1) transport, (2) ...

  11. Universitat Regensburg Imaginary Kahlerian killing

    E-print Network

    Regensburg, Universität - Naturwissenschaftliche Fakultät I

    Universit¨at Regensburg Mathematik Imaginary K¨ahlerian killing spinors I Nicolas Ginoux and Uwe Semmelmann Preprint Nr. 11/2011 #12;Imaginary K¨ahlerian Killing spinors I Nicolas Ginoux and Uwe Semmelmann manifolds admitting non-trivial imaginary K¨ahlerian Killing spinors. 1 Introduction Let (M2n , g, J) a K

  12. SUPERSYMMETRIC KILLING STRUCTURES FRANK KLINKER

    E-print Network

    Klinker, Frank

    SUPERSYMMETRIC KILLING STRUCTURES FRANK KLINKER Abstract. In this text we combine the notions definition of supersymmetric Killing structures. The latter combines subspaces of vector fields and spinor, the so called Killing equations. This discussion naturally leads to the question whether we can B

  13. Skew Killing spinors Georges Habib

    E-print Network

    Paris-Sud XI, Université de

    Skew Killing spinors Georges Habib , Julien Roth Abstract In this paper, we study the existence of a skew Killing spinor (see the definition below) on 2 and 3-dimensional Riemannian spin manifolds. We constructions (see [4, 6] for results in this topic). A -Killing spinor is a smooth section of the spinor

  14. Instantons and Killing spinors

    E-print Network

    Derek Harland; Christoph Nölle

    2011-09-20

    We investigate instantons on manifolds with Killing spinors and their cones. Examples of manifolds with Killing spinors include nearly Kaehler 6-manifolds, nearly parallel G_2-manifolds in dimension 7, Sasaki-Einstein manifolds, and 3-Sasakian manifolds. We construct a connection on the tangent bundle over these manifolds which solves the instanton equation, and also show that the instanton equation implies the Yang-Mills equation, despite the presence of torsion. We then construct instantons on the cones over these manifolds, and lift them to solutions of heterotic supergravity. Amongst our solutions are new instantons on even-dimensional Euclidean spaces, as well as the well-known BPST, quaternionic and octonionic instantons.

  15. How lymphocytes kill.

    PubMed

    Young, L H; Liu, C C; Joag, S; Rafii, S; Young, J D

    1990-01-01

    Cytotoxic T lymphocytes and natural killer cells are potent killers of target cells. These lymphocytes have large cytoplasmic granules containing cytotoxic peptides and other factors. Several of these molecules have been isolated and their functions elucidated. These molecules may be directly involved in the killing of virus-infected and transformed cells as well as in the development of cell-mediated autoimmune disorders. PMID:2184743

  16. Inactivation of Microorganisms

    Microsoft Academic Search

    Stella Maris Alzamora; Sandra N. Guerrero; Marcela Schenk; Silvia Raffellini; Aurelio López-Malo

    2011-01-01

    \\u000a Minimal processing techniques for food preservation allow better retention of product flavor, texture, color, and nutrient\\u000a content than comparable conventional treatments. A wide range of novel alternative physical factors have been intensely investigated\\u000a in the last two decades. These physical factors can cause inactivation of microorganisms at ambient or sublethal temperatures\\u000a (e.g., high hydrostatic pressure, pulsed electric fields, ultrasound, pulsed

  17. Brucella melitensis invades murine erythrocytes during infection.

    PubMed

    Vitry, Marie-Alice; Hanot Mambres, Delphine; Deghelt, Michaël; Hack, Katrin; Machelart, Arnaud; Lhomme, Frédéric; Vanderwinden, Jean-Marie; Vermeersch, Marjorie; De Trez, Carl; Pérez-Morga, David; Letesson, Jean-Jacques; Muraille, Eric

    2014-09-01

    Brucella spp. are facultative intracellular Gram-negative coccobacilli responsible for brucellosis, a worldwide zoonosis. We observed that Brucella melitensis is able to persist for several weeks in the blood of intraperitoneally infected mice and that transferred blood at any time point tested is able to induce infection in naive recipient mice. Bacterial persistence in the blood is dramatically impaired by specific antibodies induced following Brucella vaccination. In contrast to Bartonella, the type IV secretion system and flagellar expression are not critically required for the persistence of Brucella in blood. ImageStream analysis of blood cells showed that following a brief extracellular phase, Brucella is associated mainly with the erythrocytes. Examination by confocal microscopy and transmission electron microscopy formally demonstrated that B. melitensis is able to invade erythrocytes in vivo. The bacteria do not seem to multiply in erythrocytes and are found free in the cytoplasm. Our results open up new areas for investigation and should serve in the development of novel strategies for the treatment or prophylaxis of brucellosis. Invasion of erythrocytes could potentially protect the bacterial cells from the host's immune response and hamper antibiotic treatment and suggests possible Brucella transmission by bloodsucking insects in nature. PMID:25001604

  18. Invader immunology: invasion history alters immune system function in cane toads (Rhinella marina) in tropical Australia.

    PubMed

    Brown, Gregory P; Phillips, Benjamin L; Dubey, Sylvain; Shine, Richard

    2015-01-01

    Because an individual's investment into the immune system may modify its dispersal rate, immune function may evolve rapidly in an invader. We collected cane toads (Rhinella marina) from sites spanning their 75-year invasion history in Australia, bred them, and raised their progeny in standard conditions. Evolved shifts in immune function should manifest as differences in immune responses among the progeny of parents collected in different locations. Parental location did not affect the offspring's cell-mediated immune response or stress response, but blood from the offspring of invasion-front toads had more neutrophils, and was more effective at phagocytosis and killing bacteria. These latter measures of immune function are negatively correlated with rate of dispersal in free-ranging toads. Our results suggest that the invasion of tropical Australia by cane toads has resulted in rapid genetically based compensatory shifts in the aspects of immune responses that are most compromised by the rigours of long-distance dispersal. PMID:25399668

  19. Microorganisms for producing organic acids

    DOEpatents

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

    Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

  20. Charged Conformal Killing Spinors

    E-print Network

    Andree Lischewski

    2014-08-10

    We study the twistor equation on pseudo-Riemannian $Spin^c-$manifolds whose solutions we call charged conformal Killing spinors (CCKS). We derive several integrability conditions for the existence of CCKS and study their relations to spinor bilinears. A construction principle for Lorentzian manifolds admitting CCKS with nontrivial charge starting from CR-geometry is presented. We obtain a partial classification result in the Lorentzian case under the additional assumption that the associated Dirac current is normal conformal and complete the Classification of manifolds admitting CCKS in all dimensions and signatures $\\leq 5$ which has recently been initiated in the study of supersymmetric field theories on curved space.

  1. Killing the competition

    Microsoft Academic Search

    Martin Daly; Margo Wilson

    1990-01-01

    Sex- and age-specific rates of killing unrelated persons of one’s own sex were computed for Canada (1974–1983), England\\/Wales\\u000a (1977–1986), Chicago (1965–1981), and Detroit (1972) from census information and data archives of all homicides known to police.\\u000a Patterns in relation to sex and age were virtually identical among the four samples, although the rates varied enormously\\u000a (from 3.7 per million citizens

  2. Killing Horizons and Spinors

    E-print Network

    Bruno Carneiro da Cunha; Amilcar de Queiroz

    2014-06-19

    We study the near horizon geometry of generic Killing horizons constructing suitable coordinates and taking the appropriate scaling limit. We are able to show that the geometry will always show an enhancement of symmetries, and, in the extremal case, will develop a causally disconnected "throat" as expected. We analyze the implications of this to the Kerr/CFT conjecture and the attractor mechanism. We are also able to construct a set of special (pure) spinors associated with the horizon structure using their interpretation as maximally isotropic planes. The structure generalizes the usual reduced holonomy manifold in an interesting way and may be fruitful to the search of new types of compactification backgrounds.

  3. Two Different Rickettsial Bacteria Invading Volvox carteri

    PubMed Central

    Kawafune, Kaoru; Hongoh, Yuichi; Hamaji, Takashi; Sakamoto, Tomoaki; Kurata, Tetsuya; Hirooka, Shunsuke; Miyagishima, Shin-ya; Nozaki, Hisayoshi

    2015-01-01

    Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the volvocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial endosymbionts may have been transmitted to only a few algal strains very recently. However, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nuclear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lacking V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encompassing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsial gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickettsial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180. Conclusion/Significance At least two different rickettsial organisms may have invaded the V. carteri lineage, one of which may be the direct ancestor of the endosymbiont of V. carteri strain UTEX 2180, whereas the other may be closely related to the endosymbiont of P. japonica. Endosymbiotic gene transfer from the latter rickettsial organism may have occurred in an ancestor of V. carteri. Thus, the rickettsiae may be widely associated with V. carteri, and likely have often been lost during host evolution. PMID:25671568

  4. [Bioterrorism and pathogenic microorganisms].

    PubMed

    Schatzmayr, Hermann G; Barth, Ortrud Monika

    2013-10-01

    In recent years the use of pathogenic microorganisms in acts of bioterrorism has been the subject of major concern in many countries. This paper presents a possible application of viruses and bacteria for warfare and terrorist purposes, as well as a laboratory diagnosis to identify those agents. The viruses of smallpox (orthopoxvirus), of hemorrhagic fever and those belonging to filovirus have been highlighted, inter alia, as agents of human infection with bioterrorist intent. Among the bacteria, the emphasis has been on anthrax (Bacillus anthracis), the plague (Yersinia pestis), botulism (Clostridium botulinum) and tularemia (Francisella tularensis), not to mention ricin (Ricinus communis), as one of the Group B agents. PMID:24473660

  5. The race of microorganisms

    NSDL National Science Digital Library

    Exploratorium

    2004-01-01

    This reading, part of a site devoted to the science of cooking, explores how beneficial bacteria are involved in the fermentation process that is used to pickle vegetables. The reading focuses on the competition between those microorganisms that facilitate fermentation and those microbes that damage this food production process. Lactic acid bacteria are key players in the creation of pickles. The reading explains the functions of these bacteria and describes the conditions in a pickle crock--including the appropriate salt concentration, a lack of oxygen, and optimal temperature--that allow them to thrive. A sidebar points out how pickles become crunchy through osmosis. Copyright 2005 Eisenhower National Clearinghouse

  6. Drug metabolism in microorganisms.

    PubMed

    Murphy, Cormac D

    2015-01-01

    Several wild type and recombinant microorganisms can transform drugs to the equivalent human metabolites. Fungi, such as Cunninghamella spp., and Streptomyces bacteria express cytochrome P450 (CYP) enzymes that enable analogous phase I (oxidative) reactions with a wide range of drugs. The gene encoding the bifunctional CYP102A1 in Bacillus megaterium can be expressed easily in E. coli, and extensive mutagenesis experiments have generated numerous variants that can produce human drug metabolites. Additionally, human CYP isoforms have been expressed in various hosts. The application of microbial CYPs to the production of human drug metabolites is reviewed, and additional applications in the field of drug development are considered. PMID:25179825

  7. Kill operation requires thorough analysis

    SciTech Connect

    Abel, L.W. [Wild Well Control Inc., Spring, TX (United States)

    1995-05-15

    Full control of a blowout well requires a properly designed post-capping kill operation because failures in regaining well control usually occur during the kill operation, not during capping. Capping (the installation of pressure control or diverter equipment on the wellhead) is generally very reliable in gaining control of a blowout well. The following techniques are some of the viable means of killing blowout wells once the capping assemblies are in place: direct shut in of the flow; bullheading; momentum kill; volumetric control for migration of fluids or lubrication after migration ceases; and dynamic kills (friction-based dynamic kills or mass flow rate kills) The objective of most post-capping operations is to stop the flow and put the well under hydrostatic control. The means of killing a blowout once capping assemblies are in place should be chosen with care to avoid problems such as cratering, equipment failure, and underground blowouts. The particular circumstances and well integrity will dictate which kill method will be the most viable. Each of these five methods are explained.

  8. Biofilms: Survival Mechanisms of Clinically Relevant Microorganisms

    PubMed Central

    Donlan, Rodney M.; Costerton, J. William

    2002-01-01

    Though biofilms were first described by Antonie van Leeuwenhoek, the theory describing the biofilm process was not developed until 1978. We now understand that biofilms are universal, occurring in aquatic and industrial water systems as well as a large number of environments and medical devices relevant for public health. Using tools such as the scanning electron microscope and, more recently, the confocal laser scanning microscope, biofilm researchers now understand that biofilms are not unstructured, homogeneous deposits of cells and accumulated slime, but complex communities of surface-associated cells enclosed in a polymer matrix containing open water channels. Further studies have shown that the biofilm phenotype can be described in terms of the genes expressed by biofilm-associated cells. Microorganisms growing in a biofilm are highly resistant to antimicrobial agents by one or more mechanisms. Biofilm-associated microorganisms have been shown to be associated with several human diseases, such as native valve endocarditis and cystic fibrosis, and to colonize a wide variety of medical devices. Though epidemiologic evidence points to biofilms as a source of several infectious diseases, the exact mechanisms by which biofilm-associated microorganisms elicit disease are poorly understood. Detachment of cells or cell aggregates, production of endotoxin, increased resistance to the host immune system, and provision of a niche for the generation of resistant organisms are all biofilm processes which could initiate the disease process. Effective strategies to prevent or control biofilms on medical devices must take into consideration the unique and tenacious nature of biofilms. Current intervention strategies are designed to prevent initial device colonization, minimize microbial cell attachment to the device, penetrate the biofilm matrix and kill the associated cells, or remove the device from the patient. In the future, treatments may be based on inhibition of genes involved in cell attachment and biofilm formation. PMID:11932229

  9. Role of early lectin pathway activation in the complement-mediated killing of Trypanosoma cruzi.

    PubMed

    Cestari, Igor dos S; Krarup, Anders; Sim, Robert B; Inal, Jameel M; Ramirez, Marcel I

    2009-12-01

    The complement system is the first line of defence against pathogen infection and can be activated by the classic, alternative and lectin pathways. Trypanosoma cruzi, the causative agent of Chagas disease, has to evade complement system killing and invade the host cells to progress in infection. T. cruzi infectious stages resist complement-mediated killing by expressing surface receptors, which dissociate or prevent C3 convertase formation. Here, we present the first evidence that T. cruzi activates the complement lectin pathway. We detected rapid binding of mannan-binding lectin, H-ficolin, and L-ficolin to the surface of T. cruzi, and found that serum depleted of these molecules failed to kill parasites. Furthermore, lectin pathway activation by T. cruzi required the MBL-associated serine protease 2 (MASP2) activity resulting in C2 factor cleavage. In addition, we demonstrate that the infectious stage of T. cruzi inhibits the lectin pathway activation and complement killing expressing the complement C2 receptor inhibitor trispanning (CRIT) protein. Transgenic parasites overexpressing CRIT were highly resistant to complement-mediated killing. CRIT-derived peptides inhibited both C2 binding to the surface of T. cruzi and parasite killing. Biochemical studies revealed that the CRIT extracellular domain 1 inhibits MASP2 cleavage of C2 factor and thereby impairs C3 convertase formation. Our findings establish that the complement lectin pathway recognizes T. cruzi and provide molecular insights into how the infectious stage inhibits this activation to resist complement system killing. PMID:19783051

  10. Killing activity of neutrophils is mediated through activation of proteases by K+ flux

    Microsoft Academic Search

    Emer P. Reeves; Hui Lu; Hugues Lortat Jacobs; Carlo G. M. Messina; Steve Bolsover; Giorgio Gabella; Eric O. Potma; Alice Warley; Jürgen Roes; Anthony W. Segal

    2002-01-01

    According to the hitherto accepted view, neutrophils kill ingested microorganisms by subjecting them to high concentrations of highly toxic reactive oxygen species (ROS) and bringing about myeloperoxidase-catalysed halogenation. We show here that this simple scheme, which for many years has served as a satisfactory working hypothesis, is inadequate. We find that mice made deficient in neutrophil-granule proteases but normal in

  11. Male-killing bacterium in a fifth ladybird beetle, Coleomegilla maculata (Coleoptera: Coccinellidae)

    Microsoft Academic Search

    Gregory D D Hurst; Tansy C Hammarton; John J Obrycki; Tamsin M O Majerus; Linda E Walker; Dominique Bertrand; Michael E N Majerus; Gregory DD Hurst

    1996-01-01

    Inherited symbionts which selectively cause the death of male hosts are found widely across the Insecta. Previous studies have shown a single, but different micro-organism to be responsible for male-killing in each taxonomic group studied. We here produce evidence that within a group of insects, the Coccinellidae, there is more than one causal agent of male lethality. We report a

  12. Wolbachia, sex ratio bias and apparent male killing in the harlequin beetle riding pseudoscorpion

    Microsoft Academic Search

    D W Zeh; J A Zeh; M M Bonilla

    2005-01-01

    Bacterial endosymbionts that manipulate host reproduction are now known to be widespread in insects and other arthropods. Since they inhabit the cytoplasm and are maternally inherited, these microorganisms can enhance their fitness by biasing host sex ratio in favour of females. At its most extreme, sex ratio manipulation may be achieved by killing male embryos, as occurs in a number

  13. Proteolysis in hyperthermophilic microorganisms

    DOE PAGESBeta

    Ward, Donald E.; Shockley, Keith R.; Chang, Lara S.; Levy, Ryan D.; Michel, Joshua K.; Conners, Shannon B.; Kelly, Robert M.

    2002-01-01

    Proteases are found in every cell, where they recognize and break down unneeded or abnormal polypeptides or peptide-based nutrients within or outside the cell. Genome sequence data can be used to compare proteolytic enzyme inventories of different organisms as they relate to physiological needs for protein modification and hydrolysis. In this review, we exploit genome sequence data to compare hyperthermophilic microorganisms from the euryarchaeotal genusPyrococcus, the crenarchaeoteSulfolobus solfataricus, and the bacteriumThermotoga maritima. An overview of the proteases in these organisms is given based on those proteases that have been characterized and on putative proteases that have been identified from genomicmore »sequences, but have yet to be characterized. The analysis revealed both similarities and differences in the mechanisms utilized for proteolysis by each of these hyperthermophiles and indicated how these mechanisms relate to proteolysis in less thermophilic cells and organisms.« less

  14. Neutrophil Extracellular Traps Kill Bacteria

    Microsoft Academic Search

    Volker Brinkmann; Ulrike Reichard; Christian Goosmann; Beatrix Fauler; Yvonne Uhlemann; David S. Weiss; Yvette Weinrauch; Arturo Zychlinsky

    2004-01-01

    Neutrophils engulf and kill bacteria when their antimicrobial granules fuse with the phagosome. Here, we describe that, upon activation, neutrophils release granule proteins and chromatin that together form extracellular fibers that bind Gram-positive and -negative bacteria. These neutrophil extracellular traps (NETs) degrade virulence factors and kill bacteria. NETs are abundant in vivo in experimental dysentery and spontaneous human appendicitis, two

  15. 33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117...Requirements New York § 117.801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a)...

  16. 33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117...Requirements New York § 117.801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a)...

  17. 33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117...Requirements New York § 117.801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a)...

  18. 33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117...Requirements New York § 117.801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a)...

  19. How electroshock weapons kill!

    NASA Astrophysics Data System (ADS)

    Lundquist, Marjorie

    2010-03-01

    Growing numbers of law enforcement officers now carry an electroshock weapon (ESW). Over 500 U.S. deaths have followed ESW use in the past 26 years; over 450 of these deaths followed use of an electromuscular disruptor in the past 9 years. Most training courses teach that ESWs are safe; that they can kill only by the direct effect of electric current on the heart; and that a death following use of an ESW always has some other cause. All these teachings are false! The last was disproved by Lundquist.^1 Williams^2 ruled out direct electrical effects as a cause of almost all the 213 deaths he studied, leaving disruption of normal physiological processes as the only alternative explanation. Careful study of all such deaths identifies 4 different ways that death has or could have been brought about by the ESW: kidney failure following rhabdomyolysis [rare]; cardiac arrest from hyperkalemia following rhabdomyolysis [undocumented]; lactic acid-induced ventricular fibrillation [conclusive proof impossible]; and [most common] anoxia from so much lactic acid in the circulating blood that it acts as an oxygen scavenger, continuously depleting the blood of oxygen until most of the lactate has been metabolized. ^1M. Lundquist, BAPS 54(1) K1.270(2009). ^2Howard E. Williams, Taser Electronic Control Devices and Sudden In-Custody Death, 2008.

  20. Conformal Killing forms on Riemannian manifolds Habilitationsschrift

    E-print Network

    Semmelmann, Uwe

    Conformal Killing forms on Riemannian manifolds Habilitationsschrift zur Feststellung der Lehrbef Conformal Killing Forms 9 1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.2 Killing tensors and first integrals . . . . . . . . . . . . . . . . . . . . . . . . 14 2

  1. TWISTOR AND KILLING SPINORS IN LORENTZIAN GEOMETRY

    E-print Network

    Baum, Helga

    ___________________________________________________________________ TWISTOR AND KILLING* *urs de Killing lorentziens. Apr`es quelques pr'eliminaires sur les spineurs twist* *eurs- neurs de Killing r'eels. En particulier, on obtient un Theor`eme de splitt* *ing global pour les

  2. Pfiesteria shumwayae kills fish by micropredation not

    E-print Network

    .............................................................. Pfiesteria shumwayae kills fish, acute fish kills and human disease in mid-Atlantic USA estuaries1­7 . However, Pfies- teria toxins have never been isolated or characterized8 . We investigated mechanisms by which P. shumwayae kills fish

  3. Can Venus shed microorganisms?

    NASA Astrophysics Data System (ADS)

    Konesky, Gregory

    2009-08-01

    The pale featureless cloud tops of Venus reveal a rich complexity when viewed in ultraviolet. These features result from an unknown absorber brought up from lower atmospheric levels by convection, particularly at lower latitudes. While the surface of Venus is extremely hostile to life as we know it, there exists a habitable region in the atmosphere, centered at approximately 50 km, where the temperature ranges from 30 to 80ºC and the pressure is one bar. Numerous examples of cloud-borne life exist on Earth. However, the environment in the Venus atmospheric habitable zone has only a few ppm of water which is present as misty droplets, strong sulfuric acid, and intense UV illumination. The proposal that putative cloud-borne life forms in Venus' atmospheric habitable zone can be transported to Earth by a solar conveyance face several challenges. Vigorous convective mixing, especially at the lower latitudes is considered as a means of transport to the upper reaches of Venus' atmosphere. Potential propulsive forces imparted by both solar wind and sunlight pressure are considered as a means of achieving escape velocity from Venus. Additional hurdles include direct exposure by such transported life forms to the rigors of the space environment. These are contrasted to those experienced by microorganisms that may be carried within meteorites and comets. A middle ground is perhaps demonstrated by plankton that has been observed at high altitudes on Earth, likely lofted there by a hurricane, which is encased in protective ice crystals.

  4. Primary adenocarcinoma of the appendix invading the urinary bladder.

    PubMed

    Nishio, Remon; Furuya, Yuzo; Akashi, Takuya; Okumura, Akiou; Fuse, Hideki

    2006-01-01

    We report a case of adenocarcinoma of the appendix invading the urinary bladder in a 75-year-old man. Although cystoscopic examination and computed tomography suggested a primary or secondary bladder tumor, repeated transurethral bladder biopsy could not confirm the neoplasm. At operation a primary neoplasm of the appendix invading the bladder was discovered and en bloc resection of the urinary bladder with the adherent cecum followed by an ileocolonic anastomosis and ureterocutaneostomy was performed. The patient died of carcinoma 13 months later. PMID:17160444

  5. Real Killing spinors and holonomy

    Microsoft Academic Search

    Christian Bär

    1993-01-01

    We give a description of all complete simply connected Riemannian manifolds carrying real Killing spinors. Furthermore, we present a construction method for manifolds with the exceptional holonomy groupsG2 and Spin(7).

  6. Phantom Metrics With Killing Spinors

    E-print Network

    Sabra, W A

    2015-01-01

    We study metric solutions of Einstein-anti-Maxwell theory admitting Killing spinors. The analogue of the IWP metric which admits a space-like Killing vector is found and is expressed in terms of a complex function satisfying the wave equation in flat (2+1)-dimensional space-time. As examples, electric and magnetic Kasner spaces are constructed by allowing the solution to depend only on the time coordinate. Euclidean solutions are also presented.

  7. Phantom Metrics With Killing Spinors

    E-print Network

    W. A. Sabra

    2015-07-16

    We study metric solutions of Einstein-anti-Maxwell theory admitting Killing spinors. The analogue of the IWP metric which admits a space-like Killing vector is found and is expressed in terms of a complex function satisfying the wave equation in flat (2+1)-dimensional space-time. As examples, electric and magnetic Kasner spaces are constructed by allowing the solution to depend only on the time coordinate. Euclidean solutions are also presented.

  8. Angular momentum and Killing potentials

    NASA Astrophysics Data System (ADS)

    Glass, E. N.

    1996-01-01

    When the Penrose-Goldberg (PG) superpotential is used to compute the angular momentum of an axial symmetry, the Killing potential Q??(?) for that symmetry is needed. Killing potentials used in the PG superpotential must satisfy Penrose's equation. It is proved for the Schwarzschild and Kerr solutions that the Penrose equation does not admit a Q??(?) at finite r and therefore the PG superpotential can only be used to compute angular momentum asymptotically.

  9. Kills Germs by the Millions!

    ERIC Educational Resources Information Center

    Swails, Molly

    1980-01-01

    Described is a science experiment involving the isolation and study of microorganisms. Bacteria from the mouth are cultured on blood agar culture plates and are then exposed to four different mouthwashes to test their effectiveness. (DS)

  10. Digital holographic imaging of microorganisms

    E-print Network

    Wolf, Michael Trevor

    2006-01-01

    Imaging aquatic microorganisms in 3D space is of interest to biologists and ocean scientists seeking to understand the behavior of these organisms in their natural environments. In this research, digital holographic imaging ...

  11. Genetic Evolution of Software Microorganisms

    Microsoft Academic Search

    Themistoklis Panayiotopoulos; Harry Kalogirou; Anthony Petropoulos; Dionisis Dimopoulos

    2002-01-01

    Genetic Algorithms have been used in many areas of Artificial Intelligence and Artificial Life. The GA approach comes from\\u000a the area of Biology and uses the ideas of natural selection and Genetics. In this paper we present the SoftGene platform consisting\\u000a of a Virtual Machine as well as a number of evolutionary software microorganisms, which reside in it. Every microorganism

  12. INVASIONS AND INFECTIONS Invading with biological weapons: the importance of

    E-print Network

    White, Andrew

    INVASIONS AND INFECTIONS Invading with biological weapons: the importance of disease with introduced parasites), there is the potential that the disease can act as a `biological weapon' leading weapons ­ their diseases ­ with them, and concurrently, the emergence of disease within the native

  13. Culture Clash Invades Miami: Oral Histories and Ethnography Center Stage

    ERIC Educational Resources Information Center

    Garcia, David G.

    2008-01-01

    Using a critical race theory (CRT) framework, this article compares the playwriting methods of the Chicano--Latino theater trio, Culture Clash, to a counterstorytelling methodology. The author uncovers the tenets of a critical race theater in the trio's site-specific ethnographic play, "Radio Mambo: Culture Clash Invades Miami". He argues that…

  14. Harmonic Functions of Subordinate Killed Brownian Motion

    E-print Network

    Vondraèek, Zoran

    Harmonic Functions of Subordinate Killed Brownian Motion J. Glover, Z. Pop-Stojanovic, M. Rao, H of subordinate killed Brownian motion in a domain D. We first prove that, when the killed Brownian semigroup in D is intrinsic ultracontractive, all nonnegative harmonic functions of the subordinate killed Brownian motion

  15. Land-use change in a tropical mountain rainforest region of southern Ecuador affects soil microorganisms and nutrient cycling

    Microsoft Academic Search

    Karin Potthast; Ute Hamer; Franz Makeschin

    Over the past decades, the tropical mountain rainforest of southern Ecuador has been threatened by conversion to cattle pastures.\\u000a Frequently, these pastures are invaded by bracken fern and abandoned when bracken becomes dominant. Changes in land-use (forest–pasture–abandoned\\u000a pasture) can affect soil microorganisms and their physiological responses with respect to soil carbon and nutrient cycling.\\u000a In situ investigations on litter decomposition

  16. [Prevention and control of invaded plant Phytolacca americana in sandy coastal shelter forests].

    PubMed

    Fu, Jun-Peng; Li, Chuan-Rong; Xu, Jing-Wei; Cheng, Wan-Li; Song, Rui-Feng; Liu, Yun

    2012-04-01

    The invasion of Phytolacca americana has produced serious damage to the coastal shelter forests in China. In order to search for the effective measures for controlling the growth of P. americana, several plots in the Robinia pseudoacacia forest invaded by P. Americana to the relatively same extent were installed, and the measures of physical control (mowing and root cutting) and chemical control (spraying herbicides) were adopted to control the invasion of P. Americana, taking the site with good growth of Amorpha fruticosa in the forest and without any control measures as the comparison. The results showed that mowing could rapidly decrease the growth of P. americana in the same year, but the growth recovered in the next year. 1/3 root cutting only reduced the aboveground growth of P. americana in the same year, and the growth was recovered in the third year; while 2/3 root cutting and whole cutting could effectively cleanup the P. americana plants all the time. Spraying quizalofop-p-ethyl and paraquat only killed the aboveground part of P. americana in the same year, but this part of P. americana recovered to the normal level in the next year; while spraying 45 g x L(-1) of glyphosate could completely kill the whole P. americana plants till the third year. The growth of P. americana at the site with good growth of A. fruticosa and without any control measures maintained at a low level all the time, suggesting that planting A. fruticosa in R. pseudoacacia forest would be an effective approach to prevent and control the P. americana invasion. PMID:22803465

  17. Shock Compression and Recovery of Microorganism-Loaded Broths and AN Emulsion

    NASA Astrophysics Data System (ADS)

    Hazell, P. J.; Beveridge, C.; Groves, K.; Stennett, C.

    2009-12-01

    The microorganisms Escherichia coli, Enterococcus faecalis and Zygosaccharomyces bailii and an oil-based emulsion, have been subjected to shock compression using the flyer-plate technique to initial pressures of 0.8 GPa (in the suspension). In each experiment, a stainless steel capsule was used to contain the broths and allow for recovery without contamination. Where cavitation was mostly suppressed by virtue of simultaneous shock and dynamic compression, no kill was observed. By introducing an air gap behind the suspension, limited kill was measured in the yeast. Results also suggest that stable emulsification occurs in coarse oil-based emulsions that are subjected to shock.

  18. Shock compression and recovery of microorganism-loaded broths and an emulsion

    NASA Astrophysics Data System (ADS)

    Hazell, Paul; Beveridge, Cliff; Groves, Kathy

    2009-06-01

    The microorganisms Escherichia coli, Enterococcus feacalis and Zygosaccharomyces bailii and an oil-based emulsion, have been subjected to shock compression using the flyer-plate technique to initial pressures of 0.8 GPa (in the suspension). In each experiment, a stainless steel capsule was used to contain the broths and allow for recovery without contamination. Where cavitation was suppressed by virtue of simultaneous shock and quasi-static compression, no kill was observed. By introducing an air gap behind the suspension, limited kill was measured in the yeast. Results also suggest that emulsification occurs in oil-based emulsions that are subjected to shock.

  19. Phagocytosis and killing of Staphylococcus aureus by human neutrophils.

    PubMed

    Lu, Thea; Porter, Adeline R; Kennedy, Adam D; Kobayashi, Scott D; DeLeo, Frank R

    2014-01-01

    Neutrophils are essential for host defense against Staphylococcus aureus infections. Although significant progress has been made, our understanding of neutrophil interactions with S. aureus remains incomplete. To provide a more comprehensive view of this process, we investigated phagocytosis and killing of S. aureus by human neutrophils using varied assay conditions in vitro. A greater percentage of bacteria were internalized by adherent neutrophils compared to those in suspension, and, unexpectedly, uptake of S. aureus by adherent neutrophils occurred efficiently in the absence of opsonins. An antibody specific for S. aureus promoted uptake of unopsonized bacteria in suspension, but had little or no capacity to enhance phagocytosis of S. aureus opsonized with normal human serum or by adherent neutrophils. Collectively, these results indicate that assay conditions can have a significant influence on the phagocytosis and killing of S. aureus by neutrophils. More importantly, the results suggest a vaccine approach directed to enhance opsonophagocytosis alone is not sufficient to promote increased killing of S. aureus by human neutrophils. With the emergence and reemergence of antibiotic-resistant microorganisms, establishing parameters that are optimal for studying neutrophil-S. aureus interactions will pave the way towards developing immune-directed strategies for anti-staphylococcal therapies. PMID:24713863

  20. Green Frogs Show Reduced Foraging Success in Habitats Invaded by Japanese knotweed

    Microsoft Academic Search

    John C. Maerz; Bernd Blossey; Victoria Nuzzo

    2005-01-01

    Habitat loss is causing amphibian population declines worldwide, so there is increased attention to forces that degrade remaining habitats. Terrestrial habitats surrounding wetlands are critical foraging areas for temperate anurans. We investigated plant community changes in two old fields invaded by Japanese knotweed (Fallopia japonica) and the foraging success of Green frogs (Rana clamitans) in invaded and non-invaded portions of

  1. Recruitment limitation of native species in invaded coastal dune communities

    Microsoft Academic Search

    Kris French; Tanya J. Mason; Natalie Sullivan

    2011-01-01

    Recruitment limitation may limit the ability of sites to regenerate after disturbances such as weed invasion and weed management.\\u000a We investigated seed bank constraints and dispersal limitation in coastal dune communities on the east coast of Australia.\\u000a The ability of sites to regenerate naturally following weed removal was assessed in coastal dune communities invaded by the\\u000a invasive alien, bitou bush

  2. Exotic Plant Species Invade Hot Spots of Native Plant Diversity

    Microsoft Academic Search

    Thomas J. Stohlgren; Dan Binkley; Geneva W. Chong; Mohammed A. Kalkhan; Lisa D. Schell; Kelly A. Bull; Yuka Otsuki; Gregory Newman; Michael Bashkin; Yowhan Son

    1999-01-01

    Some theories and experimental studies suggest that areas of low plant spe- cies richness may be invaded more easily than areas of high plant species richness. We gathered nested-scale vegetation data on plant species richness, foliar cover, and frequency from 200 1-m2 subplots (20 1000-m2 modified-Whittaker plots) in the Colorado Rockies (USA), and 160 1-m2 subplots (16 1000-m2 plots) in

  3. EFFICACY OF OZONE IN KILLING LISTERIA MONOCYTOGENES ON ALFALFA SEEDS AND SPROUTS, AND EFFECTS ON SENSORY QUALITY OF SPROUTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was done to determine the efficacy of aqueous ozone treatment in killing Listeria monocytogenes on inoculated alfalfa seeds and sprouts. Reduction in populations of naturally occurring aerobic microorganisms on sprouts and changes in sensory quality of sprouts were also determined. Treatme...

  4. KILLING SILKWORM COCOONS BY IRRADIATION

    Microsoft Academic Search

    Tsetskhladze

    1962-01-01

    The results of investigations of silkworm cocoon killing by irradiation ; are given. It is shown that the method is a very perspective one. Its ; industrial realization will give both increased raw silk yield and improved ; dynamometric characteristics of silk thread. (auth);

  5. Does Assessment Kill Student Creativity?

    ERIC Educational Resources Information Center

    Beghetto, Ronald A.

    2005-01-01

    Does assessment kill creativity? In this article, creativity is defined and discussed and an overview of creativity and motivational research is provided to describe how assessment practices can influence students' creativity. Recommendations for protecting creativity when assessing students also are provided.

  6. Quaternionic Killing Spinors , U. Semmelmann

    E-print Network

    Semmelmann, Uwe

    Quaternionic Killing Spinors W. Kramer , U. Semmelmann , G. Weingart Mathematisches Institut der on quaternionic K¨ahler manifolds. In the present article we study the limiting case, i. e. manifolds where the lower bound is attained as an eigenvalue. We give an equivalent formulation in terms of a quaternionic

  7. The butterfly Danaus chrysippus is infected by a male-killing Spiroplasma bacterium.

    PubMed

    Jiggins, F M; Hurst, G D; Jiggins, C D; v d Schulenburg, J H; Majerus, M E

    2000-05-01

    Many insects carry maternally inherited bacteria which kill male offspring. Such bacteria will spread if male death benefits the female siblings who transmit the bacterium, and they are therefore expected in insects with antagonistic sibling interactions. We report that the butterfly Danaus chrysippus is host to a maternally inherited male-killing bacterium. Using diagnostic PCR and rDNA sequence, the bacterium was identified as a Spiroplasma closely related to 2 ladybird beetle male-killers and the tick symbiont Spiroplasma ixodetis. The male-killer was found to have a geographically restricted distribution, with up to 40% of females being infected in East Africa, but no detectable infection in small samples from other populations. Danaus chrysippus is a surprising host for a male-killer as its eggs are laid singly. This suggests that the ecological conditions permitting male-killers to invade may be more widespread than previously realized. PMID:10840973

  8. The geometry of D = 11 Killing spinors

    Microsoft Academic Search

    Jerome P. Gauntlett; Stathis Pakis

    2003-01-01

    We propose a way to classify all supersymmetric configurations of D=11 supergravity using the G-structures defined by the Killing spinors. We show that the most general bosonic geometries admitting a Killing spinor have at least a local SU(5) or an (Spin(7)l × R8) × R structure, depending on whether the Killing vector constructed from the Killing spinor is timelike or

  9. Effect of nitric oxide on staphylococcal killing and interactive effect with superoxide.

    PubMed Central

    Kaplan, S S; Lancaster, J R; Basford, R E; Simmons, R L

    1996-01-01

    The role of reactive nitrogen intermediates (RNI) such as nitric oxide (.NO) in host defense against pyogenic microorganisms is unclear, and the actual interactive effect of RNI and reactive oxidative intermediates (ROI) for microbial killing has not been determined. Since, in nature, ROI and RNI might be generated together within any local infection, we evaluated the separate and interactive effects of .NO and O2- on staphylococcal survival by using a simplified system devoid of eukaryotic cells. These studies showed that prolonged exposure of staphylococci to .NO does not result in early loss of viability but instead is associated with a dose-related delayed loss of viability. This effect is abrogated by the presence of hemoglobin, providing further evidence that the effect is RNI associated. Superoxide-mediated killing also is dose related, but in contrast to RNI-mediated killing, it is rapid and occurs within 2 h of exposure. We further show that the interaction of .NO and O(2)- results in decreased O(2)--mediated staphylococcal killing at early time points. .NO, however, appears to enhance or stabilize microbial killing over prolonged periods of incubation. This study did not produce evidence of early synergism of ROI and RNI, but it does suggest that .NO may contribute to host defense, especially when ROI-mediated killing is compromised. PMID:8557376

  10. ccsd00002799, KILLING FORMS ON SYMMETRIC SPACES

    E-print Network

    ccsd­00002799, version 1 ­ 7 Sep 2004 KILLING FORMS ON SYMMETRIC SPACES FLORIN BELGUN, ANDREI MOROIANU AND UWE SEMMELMANN Abstract. Killing forms on Riemannian manifolds are di#11;erential forms whose space carries a non{parallel Killing p{form (p #21; 2) if and only if it isometric to a Riemannian

  11. KILLING SPINORS ON LORENTZIAN MANIFOLDS CHRISTOPH BOHLE

    E-print Network

    KILLING SPINORS ON LORENTZIAN MANIFOLDS CHRISTOPH BOHLE Abstract. The aim of this paper is to describe some results concerning the geometry of Lorentzian manifolds admitting Killing spinors. We prove that there are imaginary Killing spinors on simply connected Lorentzian Einstein{Sasaki manifolds. In the Riemannian case

  12. Imaginary Kahlerian Killing spinors I Nicolas Ginoux

    E-print Network

    Semmelmann, Uwe

    Imaginary K¨ahlerian Killing spinors I Nicolas Ginoux and Uwe Semmelmann February 19, 2012 Abstract-trivial imaginary K¨ahlerian Killing spinors. 1 Introduction Let (M2n , g, J) a K¨ahler manifold of real dimension 2¨ahler manifold and C. A pair (, ) of sections of M is called an -K¨ahlerian Killing spinor if and only

  13. EXTRINSIC KILLING SPINORS OUSSAMA HIJAZI AND SEBASTI

    E-print Network

    Henri Poincaré -Nancy-Université, Université

    EXTRINSIC KILLING SPINORS OUSSAMA HIJAZI AND SEBASTI #19; AN MONTIEL Abstract. Under intrinsic that there is an isomorphism between the restriction to the boundary of parallel spinors and extrinsic Killing spinors of non-negative Killing constant. As a corollary, we prove that a complete Ricci- at spin manifold with mean

  14. Beetle Kill Wall at NREL

    SciTech Connect

    None

    2010-01-01

    When it comes to designing an interior decorative feature for one of the most energy efficient office buildings in the world, very few would consider bringing in a beetle to do the job. But thats what happened at the U.S. Department of Energy's (DOE) Research Support Facility (RSF) located on the National Renewable Energy Laboratory (NREL) campus.In June, the RSF will become home to more than 800 workers from DOE and NREL and building visitors will be greeted with a soaring, two-story high wall entirely covered with wood harvested from the bark beetle infestation that has killed millions of pine trees in the Western U.S. But, the use of beetle kill wood is just one example of the resources being leveraged to make the RSF a model for sustainability and one more step toward NRELs goal to be a net zero energy campus.

  15. Beetle Kill Wall at NREL

    ScienceCinema

    None

    2013-05-29

    When it comes to designing an interior decorative feature for one of the most energy efficient office buildings in the world, very few would consider bringing in a beetle to do the job. But thats what happened at the U.S. Department of Energy's (DOE) Research Support Facility (RSF) located on the National Renewable Energy Laboratory (NREL) campus.In June, the RSF will become home to more than 800 workers from DOE and NREL and building visitors will be greeted with a soaring, two-story high wall entirely covered with wood harvested from the bark beetle infestation that has killed millions of pine trees in the Western U.S. But, the use of beetle kill wood is just one example of the resources being leveraged to make the RSF a model for sustainability and one more step toward NRELs goal to be a net zero energy campus.

  16. Proteasomes Control Caspase-1 Activation in Anthrax Lethal Toxin-mediated Cell Killing*S

    E-print Network

    Brojatsch, Jürgen

    Proteasomes Control Caspase-1 Activation in Anthrax Lethal Toxin-mediated Cell Killing*S Received, MAPKK cleavage is insufficient for LT killing and is possibly not even required for this process (17). In the mouse model, the susceptibility of antigen-presenting cells to LT killing is strain

  17. 40 CFR 725.85 - Microorganism identity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Microorganism identity. 725.85 Section 725.85 Protection...Information § 725.85 Microorganism identity. (a) Claims applicable to the...portions of the specific microorganism identity at the time of submission of the...

  18. 40 CFR 725.85 - Microorganism identity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Microorganism identity. 725.85 Section 725.85 Protection...Information § 725.85 Microorganism identity. (a) Claims applicable to the...portions of the specific microorganism identity at the time of submission of the...

  19. Selective accumulation of heavy metals by microorganisms

    Microsoft Academic Search

    Akira Nakajima; Takashi Sakaguchi

    1986-01-01

    An investigation of the removal and recovery of urnnium from aqueous systems using microbial biomass has been described previously (Nakajima et al. 1982). To establish which microorganisms accumulate the most uranium, we extended our investigation of uranium uptake to 83 species of microorganisms, 32 bacteria, 15 yeasts, 16 fungi and 20 actinomycetes. Of these 83 species of microorganisms tested, extremely

  20. Microorganism Utilization for Synthetic Milk

    NASA Technical Reports Server (NTRS)

    Morford, Megan A.; Khodadad, Christina L.; Caro, Janicce I.; Spencer, LaShelle E.; Richards, Jeffery T.; Strayer, Richard F.; Birmele, Michele N.; Wheeler, Raymond M.

    2014-01-01

    A desired architecture for long duration spaceflight, like aboard the International Space Station or for future missions to Mars, is to provide a supply of fresh food crops for the astronauts. However, some crops can create a high proportion of inedible plant waste. The main goal of the Synthetic Biology project, Cow in a Column, was to produce the components of milk (sugar, lipid, protein) from inedible plant waste by utilizing microorganisms (fungi, yeast, bacteria). Of particular interest was utilizing the valuable polysaccharide, cellulose, found in plant waste, to naturally fuel-through microorganism cellular metabolism- the creation of sugar (glucose), lipid (milk fat), and protein (casein) in order to produce a synthetic edible food product. Environmental conditions such as pH, temperature, carbon source, aeration, and choice microorganisms were optimized in the laboratory and the desired end-products, sugars and lipids, were analyzed. Trichoderma reesei, a known cellulolytic fungus, was utilized to drive the production of glucose, with the intent that the produced glucose would serve as the carbon source for milk fat production and be a substitute for the milk sugar lactose. Lipid production would be carried out by Rhodosporidium toruloides, yeast known to accumulate those lipids that are typically found in milk fat. Results showed that glucose and total lipid content were below what was expected during this phase of experimentation. In addition, individual analysis of six fatty acids revealed that the percentage of each fatty acid was lower than naturally produced bovine milk. Overall, this research indicates that microorganisms could be utilized to breakdown inedible solid waste to produce useable products. For future work, the production of the casein protein for milk would require the development of a genetically modified organism, which was beyond the scope of the original project. Additional trials would be needed to further refine the required environment/organisms for the production of desired sugar and lipid end-products.

  1. Space and the persistence of male-killing endosymbionts in insect populations.

    PubMed

    Groenenboom, Maria A C; Hogeweg, Paulien

    2002-12-22

    Male-killing bacteria are bacteria that are transmitted vertically through the females of their insect hosts. They can distort the sex ratio of their hosts by killing infected male offspring. In nature, male-killing endosymbionts (male killers) often have a 100% efficient vertical transmission, and multiple male-killing bacteria infecting a single population are observed. We use different model formalisms to study these observations. In mean-field models a male killer with perfect transmission drives the host population to extinction, and coexistence between multiple male killers within one population is impossible; however, in spatially explicit models, both phenomena are readily observed. We show how the spatial pattern formation underlies these results. In the case of high transmission efficiencies, waves with a high density of male killers alternate with waves of mainly wild-type hosts. The male killers cause local extinction, but this creates an opportunity for uninfected hosts to re-invade these areas. Spatial pattern formation also creates an opportunity for two male killers to coexist within one population: different strains create spatial regions that are qualitatively different; these areas then serve as different niches, making coexistence possible. PMID:12573064

  2. Space and the persistence of male-killing endosymbionts in insect populations.

    PubMed Central

    Groenenboom, Maria A C; Hogeweg, Paulien

    2002-01-01

    Male-killing bacteria are bacteria that are transmitted vertically through the females of their insect hosts. They can distort the sex ratio of their hosts by killing infected male offspring. In nature, male-killing endosymbionts (male killers) often have a 100% efficient vertical transmission, and multiple male-killing bacteria infecting a single population are observed. We use different model formalisms to study these observations. In mean-field models a male killer with perfect transmission drives the host population to extinction, and coexistence between multiple male killers within one population is impossible; however, in spatially explicit models, both phenomena are readily observed. We show how the spatial pattern formation underlies these results. In the case of high transmission efficiencies, waves with a high density of male killers alternate with waves of mainly wild-type hosts. The male killers cause local extinction, but this creates an opportunity for uninfected hosts to re-invade these areas. Spatial pattern formation also creates an opportunity for two male killers to coexist within one population: different strains create spatial regions that are qualitatively different; these areas then serve as different niches, making coexistence possible. PMID:12573064

  3. Killing(-Yano) Tensors in String Theory

    E-print Network

    Chervonyi, Yuri

    2015-01-01

    We construct the Killing(-Yano) tensors for a large class of charged black holes in higher dimensions and study general properties of such tensors, in particular, their behavior under string dualities. Killing(-Yano) tensors encode the symmetries beyond isometries, which lead to insights into dynamics of particles and fields on a given geometry by providing a set of conserved quantities. By analyzing the eigenvalues of the Killing tensor, we provide a prescription for constructing several conserved quantities starting from a single object, and we demonstrate that Killing tensors in higher dimensions are always associated with ellipsoidal coordinates. We also determine the transformations of the Killing(-Yano) tensors under string dualities, and find the unique modification of the Killing-Yano equation consistent with these symmetries. These results are used to construct the explicit form of the Killing(-Yano) tensors for the Myers-Perry black hole in arbitrary number of dimensions and for its charged version.

  4. Skull invaders: when surgical pathology and neuropathology worlds collide.

    PubMed

    Serracino, Hilary S; Kleinschmidt-Demasters, B K

    2013-07-01

    Skull and dura serve as effective barriers to penetration by most tumors, often preventing masses originating intracranially from extending into the contiguous bone and soft tissues, or those arising in head and neck regions from extending into the dura and brain tissue. We review our 15-year experience with extracranial tumors that had sufficiently invaded adjacent skull, dura, or brain from the "outside-in" to require a neurosurgeon to participate in the surgical resection and discuss our 40 cases in context with the literature. Sinonasal-origin tumors (n = 17) and cutaneous tumors (n = 10) were the most frequent skull-invaders. Most of the cutaneous tumor types were squamous cellcarcinomas (n = 9); diverse sinonasal-origin types included 4 squamous cell carcinomas, 4 adenoid cystic carcinomas, 2 sinonasal undifferentiated carcinomas, 2 sinonasal adenocarcinomas, and single examples each of sinonasal-origin hemangiopericytoma, solitary fibrous tumor, melanoma, mucocele, and teratocarcinoma. There were 9olfactory neuroblastomas, and middle ear-origin basal cell carcinoma,recurrent glomus jugulare, and orbital malignant hidradenoma were also seen. Unique tumors included a cutaneous cylindroma invasive of skull convexity occurring in familial cylindromatosis and a ganglioneuroma of the middle ear with massive bilateral skull base extension. Convexity dural spread, a seldom-reported pattern of dissemination, was seen in 1 olfactory neuroblastoma and 1 adenoid cystic carcinoma. The ability to show skull/dural invasion did not correlate with specific histopathologic features; even benign tumor types can show skull/dural penetration. PMID:23771219

  5. Exotic invaders gain foraging benefits by shoaling with native fish

    PubMed Central

    Camacho-Cervantes, Morelia; Garcia, Constantino Macías; Ojanguren, Alfredo F.; Magurran, Anne E.

    2014-01-01

    Freshwater habitats are under increasing threat due to invasions of exotic fish. These invasions typically begin with the introduction of small numbers of individuals unfamiliar with the new habitat. One way in which the invaders might overcome this disadvantage is by associating with native taxa occupying a similar ecological niche. Here we used guppies (Poecilia reticulata) from a feral population in Mexico to test the prediction that exotic shoaling fish can associate with heterospecifics, and that they improve their foraging efficiency by doing so. Guppies have invaded the Mexican High Plateau and are implicated in the declines of many native topminnow (Goodeinae) species. We show that heterospecific associations between guppies and topminnows can deliver the same foraging benefits as conspecific shoals, and that variation in foraging gains is linked to differences in association tendency. These results uncover a mechanism enabling founding individuals to survive during the most vulnerable phase of an invasion and help explain why guppies have established viable populations in many parts of Mexico as well in every continent except Antarctica.

  6. Serotype M3 and M28 Group A Streptococci Have Distinct Capacities to Evade Neutrophil and TNF-? Responses and to Invade Soft Tissues

    PubMed Central

    Stetzner, Zachary W.; Li, Dengfeng; Feng, Wenchao; Liu, Mengyao; Liu, Guanghui; Wiley, James; Lei, Benfang

    2015-01-01

    The M3 Serotype of Group A Streptococcus (GAS) is one of the three most frequent serotypes associated with severe invasive GAS infections, such as necrotizing fasciitis, in the United States and other industrialized countries. The basis for this association and hypervirulence of invasive serotype M3 GAS is not fully understood. In this study, the sequenced serotype M3 strain, MGAS315, and serotype M28 strain, MGAS6180, were characterized in parallel to determine whether contemporary M3 GAS has a higher capacity to invade soft tissues than M28 GAS. In subcutaneous infection, MGAS315 invaded almost the whole skin, inhibited neutrophil recruitment and TNF-? production, and was lethal in subcutaneous infection of mice, whereas MGAS6180 did not invade skin, induced robust neutrophil infiltration and TNF-? production, and failed to kill mice. In contrast to MGAS6180, MGAS315 had covS G1370T mutation. Either replacement of the covS1370T gene with wild-type covS in MGAS315 chromosome or in trans expression of wild-type covS in MGAS315 reduced expression of CovRS-controlled virulence genes hasA, spyCEP, and sse by >10 fold. MGAS315 covSwt lost the capacity to extensively invade skin and to inhibit neutrophil recruitment and had attenuated virulence, indicating that the covS G1370T mutation critically contribute to the hypervirulence of MGAS315. Under the background of functional CovRS, MGAS315 covSwt still caused greater lesions than MGAS6180, and, consistently under the background of covS deletion, MGAS6180 ?covS caused smaller lesions than MGAS315 ?covS. Thus, contemporary invasive M3 GAS has a higher capacity to evade neutrophil and TNF-? responses and to invade soft tissue than M28 GAS and that this skin-invading capacity of M3 GAS is maximized by natural CovRS mutations. These findings enhance our understanding of the basis for the frequent association of M3 GAS with necrotizing fasciitis. PMID:26047469

  7. Desert Dust Kills Florida Fish

    NSDL National Science Digital Library

    This National Aeronautics and Space Administration (NASA) article discusses the connection between dust storms in Africa, and red tides along the Florida coast. Red tides are blooms of toxic algae that kill fish, birds, and mammals, as well as cause health problems in humans. Storm activity in the Sahara Desert region kicks up topsoil that winds transport into the Gulf of Mexico. These clouds fertilize the water with iron, which bacteria named Trichodesmium use to create nitrogen. The nitrogen makes the water a friendly environment for the toxic algae. This article discusses this process and research that is going on to help solve the problem. Audio version is available as well.

  8. How To Kill a Penguin

    E-print Network

    Ulrich Haisch

    2007-06-23

    Within constrained minimal-flavor-violation the large destructive flavor-changing Z-penguin managed to survive eradication so far. We give a incisive description of how to kill it using the precision measurements of the Z -> b anti-b pseudo observables. The derived stringent range for the non-standard contribution to the universal Inami-Lim function C leads to tight two-sided limits for the branching ratios of all Z-penguin dominated flavor-changing K- and B-decays.

  9. Fish kill from underwater explosions

    USGS Publications Warehouse

    Stuart, David J.

    1962-01-01

    The U.S. Geological Survey has used 23 different shotpoints during two seasons of field work in our seismic study of crustal structure in western United States. Without exception, it has been found that under-water shotpoints result in a more efficient conversion of explosive energy into seismic energy than do drilled-hole shotpoints. This experience, together with elimination of drilling costs, has led to the use of underwater shotpoints wherever possible. Three of the 23 shotpoints were in the Pacific Ocean, and for these we have no detailed information on the fish kill. Another six shotpoints were located in inland bodies of water. These are: * Soda Lake near Fallon, Nevada * Mono Lake near Lee Vining, California * Lake Mead near Boulder City, Nevada * Shasta Lake near Redding, California * C.J. Strike Reservoir near Bruneau, Idaho * Lucky Peak Reservoir near Boise, Idaho The 22 high-explosive charges, weighing a total of 95,100 pounds, that were fired in lakes containing fish life resulted in the known death of 2,413 game fish with a total weight of 759 pounds. The average mortality was 110 game fish or 34.5 pounds of game fish killed per average shot of 4,325 pounds of high-explosives.

  10. Killing tensors in pp-wave spacetimes

    E-print Network

    Aidan J Keane; Brian O J Tupper

    2010-11-29

    The formal solution of the second order Killing tensor equations for the general pp-wave spacetime is given. The Killing tensor equations are integrated fully for some specific pp-wave spacetimes. In particular, the complete solution is given for the conformally flat plane wave spacetimes and we find that irreducible Killing tensors arise for specific classes. The maximum number of independent irreducible Killing tensors admitted by a conformally flat plane wave spacetime is shown to be six. It is shown that every pp-wave spacetime that admits an homothety will admit a Killing tensor of Koutras type and, with the exception of the singular scale-invariant plane wave spacetimes, this Killing tensor is irreducible.

  11. Non-small cell lung cancer invading the chest wall.

    PubMed

    Riquet, Marc; Arame, Alex; Le Pimpec Barthes, Françoise

    2010-11-01

    Non-Small cell lung cancer invading the chest wall represents an advanced stage of the disease. Chest wall resection may be achieved in up to 100% of the patients, and the ensuing defect requires to be reconstructed in 40% to 64% of cases. Once a surgical challenge, chest wall resection is no longer a technical problem and en bloc chest wall and lung resections regularly provide good results. However, survival rates are jeopardized by incompleteness of the resection and mediastinal lymph node involvement. Nowadays, the challenge is represented by the use of the other nonsurgical modalities (chemotherapy and radiation therapy) to increase the chance of performing a complete resection, the need to achieve a better control of probable lymphatic or hematogenous spread, and the reduction of the recurrence rate. PMID:20974435

  12. The Lie Algebra of Local Killing Fields

    E-print Network

    Richard Atkins

    2009-09-18

    We present an algebraic procedure that finds the Lie algebra of the local Killing fields of a smooth metric. In particular, we determine the number of independent local Killing fields about a given point on the manifold. Spaces of constant curvature and locally symmetric spaces are also discussed. Furthermore, we obtain a complete classification of the Lie algebra of local Killing fields for surfaces in terms of conditions upon the Gauss curvature.

  13. Cellulolytic Microorganisms from Thermal Environments

    SciTech Connect

    Vishnivetskaya, Tatiana A [ORNL; Raman, Babu [ORNL; Phelps, Tommy Joe [ORNL; Podar, Mircea [ORNL; Elkins, James G [ORNL

    2012-01-01

    Thermal, anaerobic environments rich in decaying plant material are a potential source of novel cellulolytic bacteria. Samples collected from geothermal aquifers in the Yellowstone National Park (YNP) were used to select for cellulolytic thermophiles. Laboratory enrichments on dilute-acid pretreated plant biomass (switchgrass, Populus), and crystalline cellulose (Avicel) resulted in the isolation of 247 environmental clones. The majority of individual clones were affiliated with the cellulolytic bacteria of phylum Firmicutes, followed by xylanolytic and saccharolytic members of the phylum Dictyoglomi. Among the Firmicutes, the clones were affiliated with the genera Caldicellulosiruptor (54.4%), Caloramator (11.5%), Thermoanaerobacter (8.8%), Thermovenabulum (4.1%), and Clostridium (2.0%). From established anaerobic thermophilic enrichments a total of 81 single strains of the genera Caldicellulosiruptor (57%) and Thermoanaerobacter (43%) were isolated. With continuous flow enrichment on Avicel, increases in the relative abundance of Caloramator sp. was observed over clones detected from the Caldicellulosiruptor. Complex communities of interacting microorganisms bring about cellulose decomposition in nature, therefore using up-to-date approaches may yield novel cellulolytic microorganisms with high activity and a rapid rate of biomass conversion to biofuels.

  14. Teleparallel Killing Vectors of Spherically Symmetric Spacetimes

    E-print Network

    M. Sharif; Bushra Majeed

    2009-05-20

    In this paper, Killing vectors of spherically spacetimes have been evaluated in the context of teleparallel theory of gravitation. Further, we investigate the Killing vectors of the Friedmann metrics. It is found that for static spherically spacetimes the number of Killing vectors turn out to be \\emph{seven} while for the Friedmann models, we obtain \\emph{six} teleparallel Killing vectors. The results are then compared with those of General Relativity. We conclude that both of these descriptions of gravity do not provide the consistent results in general. However, these results may coincide under certain conditions for a particular spacetime.

  15. Timelike Killing spinors in seven dimensions

    SciTech Connect

    Cariglia, Marco; Conamhna, Oisin A.P. Mac [DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2004-12-15

    We employ the G-structure formalism to study supersymmetric solutions of minimal and SU(2) gauged supergravities in seven dimensions admitting Killing spinors with an associated timelike Killing vector. The most general such Killing spinor defines a SU(3) structure. We deduce necessary and sufficient conditions for the existence of a timelike Killing spinor on the bosonic fields of the theories, and find that such configurations generically preserve one out of 16 supersymmetries. Using our general supersymmetric ansatz we obtain numerous new solutions, including squashed or deformed anti-de Sitter solutions of the gauged theory, and a large class of Goedel-like solutions with closed timelike curves.

  16. A kill curve for Phanerozoic marine species

    NASA Technical Reports Server (NTRS)

    Raup, D. M.

    1991-01-01

    A kill curve for Phanerozoic species is developed from an analysis of the stratigraphic ranges of 17,621 genera, as compiled by Sepkoski. The kill curve shows that a typical species' risk of extinction varies greatly, with most time intervals being characterized by very low risk. The mean extinction rate of 0.25/m.y. is thus a mixture of long periods of negligible extinction and occasional pulses of much higher rate. Because the kill curve is merely a description of the fossil record, it does not speak directly to the causes of extinction. The kill curve may be useful, however, to li inverted question markmit choices of extinction mechanisms.

  17. Multiplication of certain soil micro-organisms under simulated Martian conditions.

    PubMed

    Imshenetsky, A A; Kusjurina, L A; Jakshina, V M

    1970-01-01

    According to earlier observations, severe UV irradiation kills all micro-organisms in a chamber with simulated Martian conditions. However, even a thin soil layer protects buried micro-organisms from UV irradiation. The chief limiting factor for microbial multiplication under simulated Martian conditions seems to be soil humidity. Several micro-organisms were isolated from harsh environments (e.g., from Arctic, Antarctic desert and high-mountain soil samples). A strain of an oligonitrophilic mycococcus, isolated from Dixon Island, proved to be most resistant to low humidity. It multiplied in a mixture of limonite (maximal hygroscopical humidity 3.8%) + 2% (w/w) garden soil kept in a chamber simulating Martian conditions. Total cell count increased 7.6-fold and, in some experiments, 26-fold in 14 days. The oligonitrophilic mycococcus was able to grow even at a humidity level of 2.5%, that is less than maximal hygroscopical (3.8%). Under these conditions cell count increased 10-fold in 36 days. Thus, it was shown that even in Earth soils there are xerophytic micro-organisms which are able to multiply in limonite of low humidity. These data might correct our current concepts concerning microbial water requirements. One might speculate that Martian micro-organisms belong to xerophytic species. PMID:12664919

  18. 75 FR 62469 - Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-12

    ...Coast Guard 33 CFR Part 117 [Docket No. USCG-2010-0907] Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their Tributaries, NY, Maintenance AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from...

  19. 75 FR 30299 - Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-01

    ...Coast Guard 33 CFR Part 117 [Docket No. USCG-2010-0355] Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their Tributaries, NY, Maintenance AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from...

  20. The killing consensus : homicide detectives, police that kill and organized crime in São Paulo, Brazil

    E-print Network

    Willis, Graham Arthur Neill, 1979-

    2013-01-01

    Policing is widely understood, empirically and theoretically, as a core function of the state. Much of the knowledge presumes that police are the only body that may kill and arbitrate killing, routinely and without retaliation ...

  1. A combined microfluidic/dielectrophoretic microorganism concentrator

    E-print Network

    Gadish, Nitzan

    2005-01-01

    This thesis presents the development of a high-throughput microfluidic microorganism concentrator for pathogen detection applications. Interdigitated electrodes lining the bottom of the channel use positive dielectrophoretic ...

  2. Impact of Alien Plant Invaders on Pollination Networks in Two Archipelagos

    E-print Network

    Traveset, Anna

    Impact of Alien Plant Invaders on Pollination Networks in Two Archipelagos Benigno Padro´ n1-modal) networks. We focus on the invader Opuntia spp., a cosmopolitan alien cactus. We compare two island systems. Citation: Padro´n B, Traveset A, Biedenweg T, Di´az D, Nogales M, et al. (2009) Impact of Alien Plant

  3. Pemberton et al: ALIEN TERRESTRIAL ORCHID, EULOPHIA GRAMINEA, INVADES MIAMI ALIEN TERRESTRIAL ORCHID, EULOPHIA GRAMINEA,

    E-print Network

    Koptur, Suzanne

    Pemberton et al: ALIEN TERRESTRIAL ORCHID, EULOPHIA GRAMINEA, INVADES MIAMI 183 ALIEN TERRESTRIAL ORCHID, EULOPHIA GRAMINEA, INVADES MIAMI Bob Pemberton, PhD, Suzanne Koptur, PhD & Timothy Collins, PhD We first encountered an Asian orchid, Eulophia graminea, in South Miami during the autumn of 2007

  4. HOW INVADED IS INVADED?

    EPA Science Inventory

    One thrust of invasion biology has been to compare the extent of invasion among communities and biogeographic regions. A problem with such comparisons has been the plethora of metrics used and the lack of standardization as to what data are incorporated into the metrics. One sour...

  5. Approximate Killing Vectors on S^2

    E-print Network

    Gregory B. Cook; Bernard F. Whiting

    2007-06-01

    We present a new method for computing the best approximation to a Killing vector on closed 2-surfaces that are topologically S^2. When solutions of Killing's equation do not exist, this method is shown to yield results superior to those produced by existing methods. In addition, this method appears to provide a new tool for studying the horizon geometry of distorted black holes.

  6. Bull heading to kill live gas wells

    SciTech Connect

    Oudeman, P.; Avest, D. ter; Grodal, E.O.; Asheim, H.A.; Meissner, R.J.H.

    1994-12-31

    To kill a live closed-in gas well by bull heading down the tubing, the selected pump rate should be high enough to ensure efficient displacement of the gas into the formation (i.e., to avoid the kill fluid bypassing the gas). On the other hand, the pressures that develop during bull heading at high rate must not exceed wellhead pressure rating, tubing or casing burst pressures or the formation breakdown gradient, since this will lead, at best, to a very inefficient kill job. Given these constraints, the optimum kill rate, requited hydraulic horsepower, density and type of kill fluids have to be selected. For this purpose a numerical simulator has been developed, which predicts the sequence of events during bull heading. Pressures and flow rates in the well during the kill job are calculated, taking to account slip between the gas and kill fluid, hydrostatic and friction pressure drop, wellbore gas compression and leak-off to the formation. Comparison with the results of a dedicated field test demonstrates that these parameters can be estimated accurately. Example calculations will be presented to show how the simulator can be used to identify an optimum kill scenario.

  7. Macrophages sense and kill bacteria through carbon monoxide–dependent inflammasome activation

    PubMed Central

    Wegiel, Barbara; Larsen, Rasmus; Gallo, David; Chin, Beek Yoke; Harris, Clair; Mannam, Praveen; Kaczmarek, Elzbieta; Lee, Patty J.; Zuckerbraun, Brian S.; Flavell, Richard; Soares, Miguel P.; Otterbein, Leo E.

    2014-01-01

    Microbial clearance by eukaryotes relies on complex and coordinated processes that remain poorly understood. The gasotransmitter carbon monoxide (CO) is generated by the stress-responsive enzyme heme oxygenase-1 (HO-1, encoded by Hmox1), which is highly induced in macrophages in response to bacterial infection. HO-1 deficiency results in inadequate pathogen clearance, exaggerated tissue damage, and increased mortality. Here, we determined that macrophage-generated CO promotes ATP production and release by bacteria, which then activates the Nacht, LRR, and PYD domains-containing protein 3 (NALP3) inflammasome, intensifying bacterial killing. Bacterial killing defects in HO-1–deficient murine macrophages were restored by administration of CO. Moreover, increased CO levels enhanced the bacterial clearance capacity of human macrophages and WT murine macrophages. CO-dependent bacterial clearance required the NALP3 inflammasome, as CO did not increase bacterial killing in macrophages isolated from NALP3-deficient or caspase-1–deficient mice. IL-1? cleavage and secretion were impaired in HO-1–deficient macrophages, and CO-dependent processing of IL-1? required the presence of bacteria-derived ATP. We found that bacteria remained viable to generate and release ATP in response to CO. The ATP then bound to macrophage nucleotide P2 receptors, resulting in activation of the NALP3/IL-1? inflammasome to amplify bacterial phagocytosis by macrophages. Taken together, our results indicate that macrophage-derived CO permits efficient and coordinated regulation of the host innate response to invading microbes. PMID:25295542

  8. Maternal Decidual Macrophages Inhibit NK Cell Killing of Invasive Cytotrophoblasts During Human Pregnancy1

    PubMed Central

    Co, Elizabeth C.; Gormley, Matthew; Kapidzic, Mirhan; Rosen, David B.; Scott, Marvin A.; Stolp, Haley A.R.; McMaster, Michael; Lanier, Lewis L.; Bárcena, Alicia; Fisher, Susan J.

    2013-01-01

    ABSTRACT Human pregnancy is an immunological paradox. Semiallogeneic (fetal) placental cells (extravillous cytotrophoblasts [CTBs]) invade the uterine lining (decidua), which contains a unique decidual natural killer (dNK) cell population, identified by the cell surface phenotype CD56bright CD16? CD3? and CD14+ CD206+ macrophages (dMac). Previous reports suggested that human dNK cells are not a threat to the fetoplacental unit because they are anergic. In contrast, here we showed that purified and exogenously stimulated dNK cells are capable killers of cellular targets, including semiallogeneic CTBs. However, dMacs in the decidual leukocyte (DL) population restrained dNK killing through a transforming growth factor beta1 (TGF-beta1)-dependent mechanism. Our findings support a new model whereby dNK cells, capable of killing CTBs, are prevented from doing so by neighboring macrophages, thus protecting the fetal cells from NK cell attack. We speculate that this mechanism would inhibit dNK cell-mediated killing, even under conditions where high levels of cytokines may stimulate dNK cells, which could pose a threat to the developing placenta. PMID:23553431

  9. Killing machines: three pore-forming proteins of the immune system.

    PubMed

    McCormack, Ryan; de Armas, Lesley; Shiratsuchi, Motoaki; Podack, Eckhard R

    2013-12-01

    The evolution of early multicellular eukaryotes 400-500 million years ago required a defensive strategy against microbial invasion. Pore-forming proteins containing the membrane-attack-complex-perforin (MACPF) domain were selected as the most efficient means to destroy bacteria or virally infected cells. The mechanism of pore formation by the MACPF domain is distinctive in that pore formation is purely physical and unspecific. The MACPF domain polymerizes, refolds, and inserts itself into bilayer membranes or bacterial outer cell walls. The displacement of surface lipid/carbohydrate molecules by the polymerizing MACPF domain creates clusters of large, water-filled holes that destabilize the barrier function and provide access for additional anti-bacterial or anti-viral effectors to sensitive sites that complete the destruction of the invader via enzymatic or chemical attack. The highly efficient mechanism of anti-microbial defense by a combined physical and chemical strategy using pore-forming MACPF-proteins has been retargeted during evolution of vertebrates and mammals for three purposes: (1) to kill extracellular bacteria C9/polyC9 evolved in conjunction with complement, (2) to kill virus infected and cancer cells perforin-1/polyperforin-1 CTL evolved targeted by NK and CTL, and (3) to kill intracellular bacteria transmembrane perforin-2/putative polyperforin-2 evolved targeted by phagocytic and nonphagocytic cells. Our laboratory has been involved in the discovery and description of each of the three pore-formers that will be reviewed here. PMID:24293008

  10. Momentum kill procedure can quickly control blowouts

    SciTech Connect

    Watson, W.D. (Southern International Inc., Oklahoma City, OK (United States)); Moore, P. (Preston L. Moore and Associates Inc., Norman, OK (United States))

    1993-08-30

    The momentum kill method can help in quickly regaining control of a blowing well, providing the blowing well rate and fluid properties can be estimated reasonably. The momentum of the kill fluid counteracts and overcomes the flowing momentum of formation fluids. In other words, sufficient mud density pumped at a sufficient rate is directed into the flow stream to force the escaping fluid column back into the well bore. Sufficient kill fluid hydrostatic pressure must be stacked'' in the hole so that the well remains dead after the operation. The momentum kill is not a panacea for all blowouts. An assessment must be made of the potential problems unique to this method, and certain requirements must be met if the technique is to be successful. The paper discusses some of the considerations for evaluating the use of the momentum kill method.

  11. On pseudo-Riemannian manifolds with many Killing spinors

    E-print Network

    Cortés, Vicente

    On pseudo-Riemannian manifolds with many Killing spinors D.V. Alekseevsky and V. Cort Killing spinors with the same Killing number, unless n 1 (mod 4) and s 3 (mod 4). We also prove that M is locally homogeneous if it admits k+ independent Killing spinors with Killing number and k- independent

  12. GENERALIZED KILLING SPINORS ON SPHERES ANDREI MOROIANU, UWE SEMMELMANN

    E-print Network

    Semmelmann, Uwe

    GENERALIZED KILLING SPINORS ON SPHERES ANDREI MOROIANU, UWE SEMMELMANN Abstract. We study generalized Killing spinors on round spheres Sn . We show that on the standard sphere S8 any generalized Killing spinor has to be an ordinary Killing spinor. Moreover we classify generalized Killing spinors

  13. OPTIMAL CONTROL APPLIED TO COMPETING CHEMOTHERAPEUTIC CELL-KILL STRATEGIES

    E-print Network

    Sontag, Eduardo

    OPTIMAL CONTROL APPLIED TO COMPETING CHEMOTHERAPEUTIC CELL-KILL STRATEGIES K. RENEE FISTER AND JOHN for chemotherapy. In particular, we investigate the qualitative differences between three different cell-kill models: log- kill hypothesis (cell-kill is proportional to mass); Norton­Simon hypothesis (cell-kill

  14. The Microbial Killing Effect of Airborne Ozone

    Microsoft Academic Search

    Ronny Kammer

    Microorganisms of the indoor air and surfaces represent a concern, mainly in the pharmaceutical industry, healthcare facilities and food industry. Microorganisms exist all around us, both in the surrounding air and on the surfaces. They may cause respiratory infections and other diseases, contaminate food, drugs, medical equipment and other products. Today we deal with this problem by disinfecting or sterilizing

  15. Particle-associated microorganisms in stormwater runoff

    Microsoft Academic Search

    Michael Borst; Ariamalar Selvakumar

    2003-01-01

    This research investigated the effects of blending and chemical addition before analysis of the concentration of microorganisms in stormwater runoff from a single summer storm to determine whether clumped or particle-associated organisms play a significant role. The standard membrane filtration method was used to enumerate the microorganisms. All organisms, except for Escherichia coli, showed an increase in the measured concentration

  16. Microorganisms detected by enzyme-catalyzed reaction

    NASA Technical Reports Server (NTRS)

    Vango, S. P.; Weetall, H. H.; Weliky, N.

    1966-01-01

    Enzymes detect the presence of microorganisms in soils. The enzyme lysozymi is used to release the enzyme catalase from the microorganisms in a soil sample. The catalase catalyzes the decomposition of added hydrogen peroxide to produce oxygen which is detected manometrically. The partial pressure of the oxygen serves as an index of the samples bacteria content.

  17. The role of microorganisms in aquaculture ponds

    Microsoft Academic Search

    David J. W. Moriarty

    1997-01-01

    Microorganisms have major roles in pond culture, particularly with respect to productivity, nutrient cycling, the nutrition of the cultured animals, water quality, disease control and environmental impact of the effluent. Management of the activities of microorganisms in food webs and nutrient cycling in ponds is necessary for optimising production, but the objectives will differ with the type of aquaculture, the

  18. Siderophores from marine microorganisms and their applications

    Microsoft Academic Search

    Junfeng Li; Zhenming Chi

    2004-01-01

    In view of the fact that siderophores from microorganisms in different environments have received much attention in recent\\u000a years because of their potential applications and diverse physiological functions, this review deals with siderophore-producing\\u000a marine microorganisms and the detection, chemical structure and potential applications of siderophores.

  19. Invading slugs (Arion vulgaris) can be vectors for Listeria monocytogenes

    PubMed Central

    Gismervik, K; Aspholm, M; Rørvik, LM; Bruheim, T; Andersen, A; Skaar, I

    2015-01-01

    Aims Listeriosis is a frequent silage-associated disease in ruminants. The slugs Arion vulgaris are invaders in gardens, vegetable crops and meadows for silage production. Field and laboratory studies were conducted to clarify whether slugs could host Listeria monocytogenes and thereby constitute a threat to animal feed safety. Methods and Results Selective culture of L. monocytogenes from 79 pooled slug samples (710 slugs) resulted in 43% positive, 16% with mean L. monocytogenes values of 405 CFU g?1 slug tissues. Of 62 individual slugs cultured, 11% also tested positive from surface/mucus. Multilocus sequence typing analysis of 36 isolates from different slug pools identified 20 sequence types belonging to L. monocytogenes lineages I and II. Slugs fed ?4·0 × 105 CFUL. monocytogenes, excreted viable L. monocytogenes in faeces for up to 22 days. Excretion of L. monocytogenes decreased with time, although there were indications of a short enrichment period during the first 24 h. Conclusions Arion vulgaris may act as a vector for L. monocytogenes. Significance and Impact of the Study Highly slug-contaminated grass silage may pose a potential threat to animal feed safety. PMID:25580873

  20. Lactobacillus equigenerosi Strain Le1 Invades Equine Epithelial Cells

    PubMed Central

    Botha, Marlie; Botes, Marelize; Loos, Ben; Smith, Carine

    2012-01-01

    Lactobacillus equigenerosi strain Le1, a natural inhabitant of the equine gastrointestinal tract, survived pH 3.0 and incubation in the presence of 1.5% (wt/vol) bile salts for at least 2 h. Strain Le1 showed 8% cell surface hydrophobicity, 60% auto-aggregation, and 47% coaggregation with Clostridium difficile C6. Only 1% of the cells adhered to viable buccal epithelial cells and invaded the cells within 20 min after contact. Preincubation of strain Le1 in a buffer containing pronase prevented adhesion to viable epithelial cells. Preincubation in a pepsin buffer delayed invasion from 20 min to 1 h. Strain Le1 did not adhere to nonviable epithelial cells. Administration of L. equigenerosi Le1 (1 × 109 CFU per 50 kg body weight) to healthy horses did not increase white blood cell numbers. Differential white blood cell counts and aspartate aminotransferase levels remained constant. Glucose, lactate, cholesterol, and urea levels remained constant during administration with L. equigenerosi Le1 but decreased during the week after administration. PMID:22504808

  1. Spacetime Encodings III - Second Order Killing Tensors

    E-print Network

    Jeandrew Brink

    2009-11-09

    This paper explores the Petrov type D, stationary axisymmetric vacuum (SAV) spacetimes that were found by Carter to have separable Hamilton-Jacobi equations, and thus admit a second-order Killing tensor. The derivation of the spacetimes presented in this paper borrows from ideas about dynamical systems, and illustrates concepts that can be generalized to higher- order Killing tensors. The relationship between the components of the Killing equations and metric functions are given explicitly. The origin of the four separable coordinate systems found by Carter is explained and classified in terms of the analytic structure associated with the Killing equations. A geometric picture of what the orbital invariants may represent is built. Requiring that a SAV spacetime admits a second-order Killing tensor is very restrictive, selecting very few candidates from the group of all possible SAV spacetimes. This restriction arises due to the fact that the consistency conditions associated with the Killing equations require that the field variables obey a second-order differential equation, as opposed to a fourth-order differential equation that imposes the weaker condition that the spacetime be SAV. This paper introduces ideas that could lead to the explicit computation of more general orbital invariants in the form of higher-order Killing Tensors.

  2. Killing in Okaraygua: An Inspector Irronogaray Mystery

    E-print Network

    Levine, Stuart

    2012-09-05

    1 Citation: Levine, Stuart. (2012) Killing in Okaraygua: An Inspector Irronogaray Mystery [Kindle Edition]. Amazon Digital Services, Amazon.com. Published version: http://www.amazon.com/Killing-Okaraygua-Inspector-Irronogaray- ebook.../dp/B0096TUC9K/ref=sr_1_9?ie=UTF8&qid=1347294990&sr=8-9&keywords=Stuart+Levine Description: Killing in Okaraygua is an historical novel as well as a murder mystery that takes place in an imaginary Latin American nation in the 1980s. The characters found...

  3. Novel water-based antiseptic lotion demonstrates rapid, broad-spectrum kill compared with alcohol antiseptic.

    PubMed

    Czerwinski, Steven E; Cozean, Jesse; Cozean, Colette

    2014-01-01

    A novel alcohol-based antiseptic and a novel water-based antiseptic lotion, both with a synergistic combination of antimicrobial ingredients containing 0.2% benzethonium chloride, were evaluated using the standard time-kill method against 25 FDA-specified challenge microorganisms. The purpose of the testing was to determine whether a non-alcohol product could have equivalent rapid and broad-spectrum kill to a traditional alcohol sanitizer. Both the alcohol- and water-based products showed rapid and broad-spectrum antimicrobial activity. The average 15-s kill was 99.999% of the challenge organism for the alcohol-based antiseptic and 99.971% for the water-based antiseptic. The alcohol-based product demonstrated 100% of peak efficacy (60s) within the first 15s, whereas the water-based product showed 99.97%. The novel alcohol-based antiseptic reduced concentrations of 100% of organisms by 99.999%, whereas the water-based antiseptic lotion showed the same reduction for 96% of organisms. A novel water-based antiseptic product demonstrated equivalent rapid, broad-spectrum antimicrobial activity to an alcohol-based sanitizer and provided additional benefits of reduced irritation, persistent effect, and greater efficacy against common viruses. The combination of rapid, broad-spectrum immediate kill and persistent efficacy against pathogens may have significant clinical benefit in limiting the spread of disease. PMID:24810728

  4. Giant Cell Tumor of the Temporal Bone Invading into the Pterygoid Muscle through the Temporomandibular Joint

    PubMed Central

    Mohamed, Aboshanif; Ishikawa, Kazuo; Omi, Eigo; Honda, Kohei; Suzuki, Shinsuke; Sato, Teruyuki; Fukui, Naoko; Takahasi, Masataka

    2014-01-01

    We report a case of giant cell tumor of the temporal bone invading into the pterygoid muscle through the temporomandibular joint. The patient was a 43-year-old woman who developed left ear fullness 2 years earlier with a mass in the external auditory canal. Radiologic evaluation revealed extension into the infratemporal fossa and confirmed that the tumor was invading into pterygoid muscle. A middle cranial fossa approach along with tympanoplasty was used for total resection of the tumor. Once a tumor invades into muscle tissue, meticulous care is required to remove it because identification of tumor tissue becomes extremely difficult. PMID:25083373

  5. Grassland invader responses to realistic changes in native species richness.

    PubMed

    Rinella, Matthew J; Pokorny, Monica L; Rekaya, Romdhane

    2007-09-01

    The importance of species richness for repelling exotic plant invasions varies from ecosystem to ecosystem. Thus, in order to prioritize conservation objectives, it is critical to identify those ecosystems where decreasing richness will most greatly magnify invasion risks. Our goal was to determine if invasion risks greatly increase in response to common reductions in grassland species richness. We imposed treatments that mimic management-induced reductions in grassland species richness (i.e., removal of shallow- and/or deep-rooted forbs and/or grasses and/or cryptogam layers). Then we introduced and monitored the performance of a notorious invasive species (i.e., Centaurea maculosa). We found that, on a per-gram-of-biomass basis, each resident plant group similarly suppressed invader growth. Hence, with respect to preventing C. maculosa invasions, maintaining overall productivity is probably more important than maintaining the productivity of particular plant groups or species. But at the sites we studied, all plant groups may be needed to maintain overall productivity because removing forbs decreased overall productivity in two of three years. Alternatively, removing forbs increased productivity in another year, and this led us to posit that removing forbs may inflate the temporal productivity variance as opposed to greatly affecting time-averaged productivity. In either case, overall productivity responses to single plant group removals were inconsistent and fairly modest, and only when all plant groups were removed did C. maculosa growth increase substantially over a no-removal treatment. As such, it seems that intense disturbances (e.g., prolonged drought, overgrazing) that deplete multiple plant groups may often be a prerequisite for C. maculosa invasion. PMID:17913143

  6. T cells kill bacteria captured by transinfection from dendritic cells and confer protection in mice.

    PubMed

    Cruz-Adalia, Aránzazu; Ramirez-Santiago, Guillermo; Calabia-Linares, Carmen; Torres-Torresano, Mónica; Feo, Lidia; Galán-Díez, Marta; Fernández-Ruiz, Elena; Pereiro, Eva; Guttmann, Peter; Chiappi, Michele; Schneider, Gerd; Carrascosa, José López; Chichón, Francisco Javier; Martínez Del Hoyo, Gloria; Sánchez-Madrid, Francisco; Veiga, Esteban

    2014-05-14

    Dendritic cells (DCs) phagocytose, process, and present bacterial antigens to T lymphocytes to trigger adaptive immunity. In vivo, bacteria can also be found inside T lymphocytes. However, T cells are refractory to direct bacterial infection, leaving the mechanisms by which bacteria invade T cells unclear. We show that T cells take up bacteria from infected DCs by the process of transinfection, which requires direct contact between the two cells and is enhanced by antigen recognition. Prior to transfer, bacteria localize to the immunological synapse, an intimate DC/T cell contact structure that activates T cells. Strikingly, T cells efficiently eliminate the transinfecting bacteria within the first hours after infection. Transinfected T cells produced high levels of proinflammatory cytokines and were able to protect mice from bacterial challenge following adoptive transfer. Thus, T lymphocytes can capture and kill bacteria in a manner reminiscent of innate immunity. PMID:24832455

  7. Ecological approaches to oral biofilms: control without killing.

    PubMed

    Marsh, Phil D; Head, David A; Devine, Deirdre A

    2015-01-01

    Humans have co-evolved with micro-organisms and have a symbiotic or mutualistic relationship with their resident microbiome. As at other body surfaces, the mouth has a diverse microbiota that grows on oral surfaces as structurally and functionally organised biofilms. The oral microbiota is natural and provides important benefits to the host, including immunological priming, down-regulation of excessive pro-inflammatory responses, regulation of gastrointestinal and cardiovascular systems, and colonisation by exogenous microbes. On occasions, this symbiotic relationship breaks down, and previously minor components of the microbiota outcompete beneficial bacteria, thereby increasing the risk of disease. Antimicrobial agents have been formulated into many oral care products to augment mechanical plaque control. A delicate balance is needed, however, to control the oral microbiota at levels compatible with health, without killing beneficial bacteria and losing the key benefits delivered by these resident microbes. These antimicrobial agents may achieve this by virtue of their recommended twice daily topical use, which results in pharmacokinetic profiles indicating that they are retained in the mouth for relatively long periods at sublethal levels. At these concentrations they are still able to inhibit bacterial traits implicated in disease (e.g. sugar transport/acid production; protease activity) and retard growth without eliminating beneficial species. In silico modelling studies have been performed which support the concept that either reducing the frequency of acid challenge and/or the terminal pH, or by merely slowing bacterial growth, results in maintaining a community of beneficial bacteria under conditions that might otherwise lead to disease (control without killing). PMID:25871418

  8. A Simple in vitro PK/PD Model System to Determine Time-Kill Curves of Drugs against Mycobacteria

    PubMed Central

    Budha, Nageshwar R.; Lee, Robin B.; Hurdle, Julian G.; Lee, Richard E.; Meibohm, Bernd

    2009-01-01

    In vivo tuberculosis is exposed to continually changing drug concentrations for which static minimum inhibitory concentration (MIC) testing may be a poor surrogate. While in vitro approaches to determine time-kill curves for antibiotics have been widely applied in assessing antimicrobial activity against fast growing microorganisms, their availability and application for slow growing microorganisms including M. tuberculosis has so far been scarce. Thus, we developed a novel simple in vitro pharmacokinetic/pharmacodynamic (PK/PD) model for establishing time-kill curves and applied it for evaluating the antimicrobial activity of different dosing regimens of isoniazid (INH) against Mycobacterium bovis BCG as a surrogate for virulent M. tuberculosis. In the in vitro model M. bovis BCG was exposed to INH concentration-time profiles as usually encountered during multiple dose therapy with 25, 100 and 300 mg/day in humans who are fast or slow INH metabolizers. Bacterial killing was followed over time by determining viable counts and the resulting time-kill data was analyzed using a semimechanistic PK/PD model with an adaptive IC50 function to describe the emergence of insensitive populations of bacteria over the course of treatment. In agreement with previous studies, the time-kill data suggest that AUC0-24/MIC is the PK/PD index that is the most explanatory of the antimicrobial effect of INH. The presented in vitro PK/PD model and associated modeling approach were able to characterize the time-kill kinetics of INH in M. bovis BCG, and may in general serve as a potentially valuable, low cost tool for the assessment of antibacterial activity in slow growing organisms in drug development and applied pharmacotherapy. PMID:19748318

  9. Quantum integrability of quadratic Killing tensors

    SciTech Connect

    Duval, C.; Valent, G. [Centre de Physique Theorique, CNRS, Luminy, Case 907, F-13288 Marseille Cedex 9 (France); Laboratoire de Physique Theorique et des Hautes Energies, 2, Place Jussieu, F-75251 Paris Cedex 5 (France)

    2005-05-01

    Quantum integrability of classical integrable systems given by quadratic Killing tensors on curved configuration spaces is investigated. It is proven that, using a 'minimal' quantization scheme, quantum integrability is ensured for a large class of classic examples.

  10. Teleparallel Killing Vectors of the Einstein Universe

    E-print Network

    M. Sharif; M. Jamil Amir

    2007-08-27

    In this short paper we establish the definition of the Lie derivative of a second rank tensor in the context of teleparallel theory of gravity and also extend it for a general tensor of rank $p+q$. This definition is then used to find Killing vectors of the Einstein universe. It turns out that Killing vectors of the Einstein universe in the teleparallel theory are the same as in General Relativity.

  11. Killing Vector Fields and Superharmonic Field Theories

    E-print Network

    Josua Groeger

    2013-01-23

    The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, referred to as superharmonic action, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of the superharmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.

  12. Killing vector fields and harmonic superfield theories

    SciTech Connect

    Groeger, Josua, E-mail: groegerj@mathematik.hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Mathematik, Rudower Chaussee 25, 12489 Berlin (Germany)

    2014-09-15

    The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, also referred to as harmonic, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of this harmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.

  13. Hazardous materials in Fresh Kills landfill

    SciTech Connect

    Hirschhorn, J.S. [Hirschhorn and Associates, Wheaton, MD (United States)

    1997-12-31

    No environmental monitoring and corrective action programs can pinpoint multiple locations of hazardous materials the total amount of them in a large landfill. Yet the consequences of hazardous materials in MSW landfills are considerable, in terms of public health concerns, environmental damage, and cleanup costs. In this paper a rough estimation is made of how much hazardous material may have been disposed in Fresh Kills landfill in Staten Island, New York. The logic and methods could be used for other MSW landfills. Fresh Kills has frequently been described as the world`s largest MSW landfill. While records of hazardous waste disposal at Fresh Kills over nearly 50 years of operation certainly do not exist, no reasonable person would argue with the conclusion that large quantities of hazardous waste surely have been disposed at Fresh Kills, both legally and illegally. This study found that at least 2 million tons of hazardous wastes and substances have been disposed at Fresh Kills since 1948. Major sources are: household hazardous waste, commercial RCRA hazardous waste, incinerator ash, and commercial non-RCRA hazardous waste, governmental RCRA hazardous waste. Illegal disposal of hazardous waste surely has contributed even more. This is a sufficient amount to cause serious environmental contamination and releases, especially from such a landfill without an engineered liner system, for example. This figure is roughly 1% of the total amount of waste disposed in Fresh Kills since 1948, probably at least 200 million tons.

  14. Cryptic Fitness Advantage: Diploids Invade Haploid Populations Despite Lacking Any Apparent Advantage as

    E-print Network

    Otto, Sarah

    Cryptic Fitness Advantage: Diploids Invade Haploid Populations Despite Lacking Any Apparent Advantage as Measured by Standard Fitness Assays Aleeza C. Gerstein*, Sarah P. Otto Zoology Department. Surprisingly, none of our fitness component measures (lag phase, growth rate, biomass production) indicated

  15. Decline in exotic tree density facilitates increased plant diversity: the experience from Melaleuca quinquenervia invaded wetlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Australian tree Melaleuca quinquenervia (melaleuca) formed dense monocultural forests several decades after invading Florida and the Caribbean islands. These dominant forests have displaced native vegetation in sensitive wetland systems. We hypothesized that native plant diversity would increa...

  16. Success of seeding native compared with introduced perennial vegetation for revegetating medusahead-invaded sagebrush rangeland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Millions of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle &Young) rangeland have been invaded by medusahead (Taeniatherum caput-medusae [L.] Nevski), an exotic annual grass that degrades wildlife habitat, reduces forage production, and decreases biodiversity....

  17. Mass Spectrometry for Rapid Characterization of Microorganisms

    NASA Astrophysics Data System (ADS)

    Demirev, Plamen A.; Fenselau, Catherine

    2008-07-01

    Advances in instrumentation, proteomics, and bioinformatics have contributed to the successful applications of mass spectrometry (MS) for detection, identification, and classification of microorganisms. These MS applications are based on the detection of organism-specific biomarker molecules, which allow differentiation between organisms to be made. Intact proteins, their proteolytic peptides, and nonribosomal peptides have been successfully utilized as biomarkers. Sequence-specific fragments for biomarkers are generated by tandem MS of intact proteins or proteolytic peptides, obtained after, for instance, microwave-assisted acid hydrolysis. In combination with proteome database searching, individual biomarker proteins are unambiguously identified from their tandem mass spectra, and from there the source microorganism is also identified. Such top-down or bottom-up proteomics approaches permit rapid, sensitive, and confident characterization of individual microorganisms in mixtures and are reviewed here. Examples of MS-based functional assays for detection of targeted microorganisms, e.g., Bacillus anthracis, in environmental or clinically relevant backgrounds are also reviewed.

  18. Long-term population dynamics of seeded plants in invaded grasslands.

    PubMed

    Rinella, Matthew J; Mangold, Jane M; Espeland, Erin K; Sheley, Roger L; Jacobs, James S

    2012-06-01

    In recent decades, dozens of studies have involved attempts to introduce native and desirable nonnative plant species into grasslands dominated by invasive weeds. The newly introduced plants have proved capable of establishing, but because they are rarely monitored for more than four years, it is unknown if they have a high likelihood of persisting and suppressing invaders for the long-term. Beyond invaded grasslands, this lack of long-term monitoring is a general problem plaguing efforts to reintroduce a range of taxa into a range of ecosystems. We introduced species from seed and then periodically measured plant abundances for nine years at one site and 15 years at a second site. To our knowledge, our 15-year data are the longest to date from a seeding experiment in invaded, never-cultivated grassland. At one site, three seeded grasses maintained high densities for three or more years, but then all or nearly all individuals died. At the second site, one grass performed similarly, but two other grasses proliferated and at least one greatly suppressed the dominant invader (Centaurea maculosa). In one study, our point estimate suggests that the seeded grass Thinopyrum intermedium reduced C. maculosa biomass by 93% 15 years after seeding. In some cases, data from three and fewer years after seeding falsely suggested that seeded species were capable of persisting within the invaded grassland. In other cases, data from as late as nine years after seeding falsely suggested seeded populations would not become large enough to suppress the invader. These results show that seeded species sometimes persist and suppress invaders for long periods, but short-term data cannot predict if, when, or where this will occur. Because short-term data are not predictive of long-term seeded species performances, additional long-term data are needed to identify effective practices, traits, and species for revegetating invaded grasslands. PMID:22827138

  19. Interactions among invaders: community and ecosystem effects of multiple invasive species in an experimental aquatic system

    Microsoft Academic Search

    Pieter T. J. Johnson; Julian D. Olden; Christopher T. Solomon; M. Jake Vander Zanden

    2009-01-01

    With ecosystems increasingly supporting multiple invasive species, interactions among invaders could magnify or ameliorate\\u000a the undesired consequences for native communities and ecosystems. We evaluated the individual and combined effects of rusty\\u000a crayfish (Orconectes rusticus) and Chinese mystery snails [Bellamya (=Cipangopaludina) chinensis] on native snail communities (Physa, Helisoma and Lymnaea sp.) and ecosystem attributes (algal chlorophyll a and nutrient concentrations). Both invaders

  20. Resident-Invader Phylogenetic Relatedness, Not Resident Phylogenetic Diversity, Controls Community Invasibility.

    PubMed

    Tan, Jiaqi; Pu, Zhichao; Ryberg, Wade A; Jiang, Lin

    2015-07-01

    A central goal of invasion biology is to elucidate mechanisms regulating community invasibility. Darwin's naturalization hypothesis, one of the oldest hypotheses in invasion biology, emphasizes the importance of phylogenetic relatedness (PR) between resident and invader species for predicting invasibility. Alternatively, a recent extension of the diversity-invasibility hypothesis predicts that phylogenetic diversity (PD) of resident communities influences invasibility. Neither of these hypotheses has undergone rigorous experimental testing, and the relative contributions of PR and PD to community invasibility are unknown, in part because their effects tend to be confounded with each other. Here we consider both perspectives together by independently manipulating PR and PD in laboratory bacterial assemblages. We found that, although invader abundance decreased significantly as PR increased, it was unaffected by PD. Likewise, we found that resident-invader functional similarity, not functional diversity of resident communities, was a significant predictor of invader abundance. Nevertheless, invader abundance was better predicted by PR than by functional similarity. These results highlight the importance of considering species evolutionary relationships, especially the PR between resident and invader species, for the prediction, prevention, and management of biological invasions. PMID:26098339

  1. Approximate Killing Vectors for Computing Spin in Black-Hole

    E-print Network

    Cook, Greg

    Approximate Killing Vectors for Computing Spin in Black-Hole Initial Data and Evolutions Gregory B-local definition: e.g. Brown & York[2] or Ashtekar & Krishnan[1] S = - 1 8 BH Kiji sj hd2 x i = i CK : Killing vector of ~hij conformal Killing vector of hij i AKV : Approximate Killing vector of hij ­ Greg Cook

  2. Approximate Killing Vectors and Black-Hole Diagnostics

    E-print Network

    Cook, Greg

    Approximate Killing Vectors and Black-Hole Diagnostics Gregory B. Cook Wake Forest University[2] or Ashtekar & Krishnan[1] S = - 1 8 BH Kiji sj hd2 x i = i CK : Killing vector of ~hij conformal Killing vector of hij i AKV : Approximate Killing vector of hij ­ Greg Cook ­ (WFU Physics) 1 #12

  3. Potassium Channels Mediate Killing by Human Natural Killer Cells

    Microsoft Academic Search

    Lyanne Schlichter; Neil Sidell; Susumu Hagiwara

    1986-01-01

    Human natural killer (NK) cells in peripheral blood spontaneously recognize and kill a wide variety of target cells. It has been suggested that ion channels are involved in the killing process because there is a Ca-dependent stage and because killing by presensitized cytotoxic T lymphocytes, which in many respects resembles NK killing, is associated with changes in K and Na

  4. Rapid Kill—Novel Endodontic Sealer and Enterococcus faecalis

    PubMed Central

    Zaltsman, Nathan; Houri-Haddad, Yael; Abramovitz, Itzhak; Davidi, Michael Perez; Weiss, Ervin I.

    2013-01-01

    With growing concern over bacterial resistance, the identification of new antimicrobial means is paramount. In the oral cavity microorganisms are essential to the development of periradicular diseases and are the major causative factors associated with endodontic treatment failure. As quaternary ammonium compounds have the ability to kill a wide array of bacteria through electrostatic interactions with multiple anionic targets on the bacterial surface, it is likely that they can overcome bacterial resistance. Melding these ideas, we investigated the potency of a novel endodontic sealer in limiting Enterococcus faecalis growth. We used a polyethyleneimine scaffold to synthesize nano-sized particles, optimized for incorporation into an epoxy-based endodontic sealer. The novel endodontic sealer was tested for its antimicrobial efficacy and evaluated for biocompatibility and physical eligibility. Our results show that the novel sealer foundation affixes the nanoparticles, achieving surface bactericidal properties, but at the same time impeding nanoparticle penetration into eukaryotic cells and thereby mitigating a possible toxic effect. Moreover, adequate physical properties are maintained. The nanosized quaternary amine particles interact within minutes with bacteria, triggering cell death across wide pH values. Throughout this study we demonstrate a new antibacterial perspective for endodontic sealers; a novel antibacterial, effective and safe antimicrobial means. PMID:24223159

  5. Engineered Protease-resistant Antibodies with Selectable Cell-killing Functions*

    PubMed Central

    Kinder, Michelle; Greenplate, Allison R.; Grugan, Katharine D.; Soring, Keri L.; Heeringa, Katharine A.; McCarthy, Stephen G.; Bannish, Gregory; Perpetua, Meredith; Lynch, Frank; Jordan, Robert E.; Strohl, William R.; Brezski, Randall J.

    2013-01-01

    Molecularly engineered antibodies with fit-for-purpose properties will differentiate next generation antibody therapeutics from traditional IgG1 scaffolds. One requirement for engineering the most appropriate properties for a particular therapeutic area is an understanding of the intricacies of the target microenvironment in which the antibody is expected to function. Our group and others have demonstrated that proteases secreted by invasive tumors and pathological microorganisms are capable of cleaving human IgG1, the most commonly adopted isotype among monoclonal antibody therapeutics. Specific cleavage in the lower hinge of IgG1 results in a loss of Fc-mediated cell-killing functions without a concomitant loss of antigen binding capability or circulating antibody half-life. Proteolytic cleavage in the hinge region by tumor-associated or microbial proteases is postulated as a means of evading host immune responses, and antibodies engineered with potent cell-killing functions that are also resistant to hinge proteolysis are of interest. Mutation of the lower hinge region of an IgG1 resulted in protease resistance but also resulted in a profound loss of Fc-mediated cell-killing functions. In the present study, we demonstrate that specific mutations of the CH2 domain in conjunction with lower hinge mutations can restore and sometimes enhance cell-killing functions while still retaining protease resistance. By identifying mutations that can restore either complement- or Fc? receptor-mediated functions on a protease-resistant scaffold, we were able to generate a novel protease-resistant platform with selective cell-killing functionality. PMID:23986451

  6. Effect on microorganisms of volatile compounds released from germinating seeds.

    PubMed

    Schenck, S; Stotzky, G

    1975-10-01

    Volatile compounds evolved from germinating seeds of slash pine, bean, cabbage, corn, cucumber, and pea were evaluated for their ability to support growth of microorganisms in liquid mineral salts media lacking a carbon source. Growth of eight bacteria was measured turbidimetrically and of six fungi as dry weight of mycelium. Volatiles caused increased growth of Pseudomonas fluorescens, Bacillus cereus, Erwinia carotovora, Agrobacterium tumefaciens, A. radiobacter, Rhizobium japonicum, Mucor mucedo, Fusarium oxysporum f. conglutinans, Trichoderma viride, and Penicillium vermiculatum but not of Sarcina lutea, Serratia marcescens, Chaetomium globosum, or Schizophyllum commune. Spores of Trichoderma viride showed higher germination in the presence of volatiles. Effects on growth were apparent only during the first 3 or 4 days after planting the seeds. Killed or dried seeds had no effect. The volatiles did not support microbial growth in the absence of nitrogen nor did they supply growth factors. Passing volatiles through KMnO4 or hydrazone reduced growth of the bacteria, indicating that oxidizable organic compounds, primarily aldehydes, were the active components. The volatiles were not absorbed by sterile soil, clay minerals, or water, but they were absorbed by non-steril soil and activated charcoal. PMID:1201509

  7. Effect of Microorganisms on In Situ Uranium Mining

    PubMed Central

    Yates, Marylynn V.; Brierley, James A.; Brierley, Corale L.; Follin, Steven

    1983-01-01

    The extraction of some metal values, e.g., uranium or copper, may be accomplished by using solutions to remove metals from ore bodies without practicing conventional mining. This process is referred to as in situ leaching and has been used industrially to recover uranium. The growth of microbial populations during in situ leaching is believed to be one of the causes of flow path plugging in the ore body, which results in decreased uranium production. Leach solution and solid samples from well casings and submersible pumps were collected from an in situ mining operation experiencing plugging problems. Bacillus sp., Micrococcus sp., pseudomonads, and xanthomonads were isolated from these samples in concentrations of 105 CFU ml?1. A mixed culture of these organisms was inoculated into a uranium core specimen in the laboratory to assess the role of microbes in the plugging problem. A one-third decrease in permeability was effected in 16 days. Hydrogen peroxide (0.2 g liter?1) killed the microorganisms in the core and alleviated the plugging problem. Periodically injecting hydrogen peroxide into the ore body through the production wells may reduce microbial plugging problems. PMID:16346395

  8. Kill fluid for oil field operations

    SciTech Connect

    Sydansk, R.D.

    1990-08-14

    This patent describes a process employing a kill fluid to substantially reduce the volumetric flow of formation fluid into a wellbore penetrating a formation containing the formation fluid below an earthen surface. It comprises: admixing components of a continuous flowing gel at the surface comprising of water-soluble carboxylate-containing polymer, a complex capable of crosslinking the polymer and formed of at least one electropositive chromium III species and at least one electronegative carboxylatespecies, and an aqueous solvent for the polymer and the complex; crosslinking the polymer and the complex to form the gel, wherein the kill fluid comprises the gel; placing a volume of the kill fluid in the wellbore sufficient to create a hydrostatic head which exerts a kill fluid pressure against the formation fluid substantially equal to or greater than the formation fluid pressure and thereby substantially reduces the volumetric flow of the formation fluid into the wellbore; performing an oil field operation after placing the volume of the kill fluid in the wellbore; and removing the gel from the wellbore to substantially restore the volumetric flow of the formation fluid into the wellbore.

  9. Most cross-sex killings involve the killing of a spouse (Daly & Wilson, 1999). With occasional exceptions, men far out-

    E-print Network

    Pillow, Jonathan

    Most cross-sex killings involve the killing of a spouse (Daly & Wilson, 1999). With occasional, 1988; Dobash & Dobash, 1979). These killings present a puzzle for social scientists: Why would, 1988). According to this hypothesis, the risk of getting killed is a function of the frequency

  10. Community impacts of anthropogenic disturbance: natural enemies exploit multiple routes in pursuit of invading herbivore hosts

    PubMed Central

    2010-01-01

    Background Biological invasions provide a window on the process of community assembly. In particular, tracking natural enemy recruitment to invading hosts can reveal the relative roles of co-evolution (including local adaptation) and ecological sorting. We use molecular data to examine colonisation of northern Europe by the parasitoid Megastigmus stigmatizans following invasions of its herbivorous oak gallwasp hosts from the Balkans. Local host adaptation predicts that invading gallwasp populations will have been tracked primarily by sympatric Balkan populations of M. stigmatizans (Host Pursuit Hypothesis). Alternatively, ecological sorting allows parasitoid recruitment from geographically distinct populations with no recent experience of the invading hosts (Host Shift Hypothesis). Finally, we test for long-term persistence of parasitoids introduced via human trade of their hosts' galls (Introduction Hypothesis). Results Polymorphism diagnostic of different southern refugial regions was present in both mitochondrial and nuclear microsatellite markers, allowing us to identify the origins of northern European invaded range M. stigmatizans populations. As with their hosts, some invaded range populations showed genetic variation diagnostic of Balkan sources, supporting the Host Pursuit Hypothesis. In contrast, other invading populations had an Iberian origin, unlike their hosts in northern Europe, supporting the Host Shift Hypothesis. Finally, both British and Italian M. stigmatizans populations show signatures compatible with the Introduction Hypothesis from eastern Mediterranean sources. Conclusions These data reveal the continental scale of multi-trophic impacts of anthropogenic disturbance and highlight the fact that herbivores and their natural enemies may face very different constraints on range expansion. The ability of natural enemies to exploit ecologically-similar hosts with which they have had no historical association supports a major role for ecological sorting processes in the recent assembly of these communities. The multitude of origins of invading natural enemy populations in this study emphasises the diversity of mechanisms requiring consideration when predicting consequences of other biological invasions or biological control introductions. PMID:20969799

  11. Selective tumor kill of cerebral glioma by photodynamic therapy using a boronated porphyrin photosensitizer.

    PubMed Central

    Hill, J S; Kahl, S B; Stylli, S S; Nakamura, Y; Koo, M S; Kaye, A H

    1995-01-01

    The prognosis for patients with the high-grade cerebral glioma glioblastoma multiforme is poor. The median survival for primary tumors is < 12 months, with most recurring at the site of the original tumor, indicating that a more aggressive local therapy is required to eradicate the unresectable "nests" of tumor cells invading into adjacent brain. Two adjuvant therapies with the potential to destroy these cells are porphyrin-sensitized photodynamic therapy (PDT) and boron-sensitized boron neutron capture therapy (BNCT). The ability of a boronated porphyrin, 2,4-(alpha, beta-dihydroxyethyl) deuteroporphyrin IX tetrakiscarborane carboxylate ester (BOPP), to act as a photosensitizing agent was investigated in vitro with the C6 rat glioma cell line and in vivo with C6 cells grown as an intracerebral tumor after implantation into Wistar rats. These studies determined the doses of BOPP and light required to achieve maximal cell kill in vitro and selective tumor kill in vivo. The data show that BOPP is more dose effective in vivo by a factor of 10 than the current clinically used photosensitizer hematoporphyrin derivative and suggest that BOPP may have potential as a dual PDT/BNCT sensitizer. Images Fig. 3 PMID:8618857

  12. Extracellular killing of inhaled pneumococci in rats

    SciTech Connect

    Coonrod, J.D.; Marple, S.; Holmes, G.P.; Rehm, S.R.

    1987-12-01

    Early clearance of inhaled Staphylococcus aureus is believed to be caused by phagocytosis by alveolar macrophages. In murine models inhaled pneumococci are cleared even more rapidly than S. aureus. Conventional opsonins appear to play no role in this clearance, and recently it has been shown that murine alveolar lining material contains free fatty acids and other soluble factors that are directly bactericidal for pneumococci. To determine whether non-phagocytic factors are involved in pneumococcal clearance, we compared the site of killing of inhaled pneumococci and S. aureus in rats using histologic methods and bronchoalveolar lavage. Spontaneous lysis of pneumococci was prevented by use of autolysin-defective pneumococci or by substitution of ethanolamine for choline in the cell wall. Histologic studies showed that the percent of inhaled staphylococci associated with alveolar macrophages always exceeded the percent of staphylococci cleared, whereas there was little association of pneumococci with macrophages during clearance. Analysis of the intracellular or extracellular location of iron 59 in bronchoalveolar lavage fluid of rats that had inhaled aerosols of /sup 59/Fe-labeled bacteria suggested that staphylococci were killed predominantly in macrophages and pneumococci in the extracellular space. When /sup 59/Fe-labeled pneumococci or staphylococci were ingested and killed by macrophages in vitro, the /sup 59/Fe remained with the macrophages, suggesting that the extracellular location of /sup 59/Fe during pneumococcal killing in vivo was not caused by rapid turnover of /sup 59/Fe in macrophages. Studies of the site of killing of inhaled type 25 pneumococci labeled exclusively in the cell wall with carbon 14-ethanolamine confirmed the results obtained with /sup 59/Fe-labeled pneumococci. Thus, early killing of inhaled pneumococci, unlike staphylococci, appears to take place outside of macrophages.

  13. Approximate Killing Fields as an Eigenvalue Problem

    E-print Network

    Christopher Beetle

    2008-08-12

    Approximate Killing vector fields are expected to help define physically meaningful spins for non-symmetric black holes in general relativity. However, it is not obvious how such fields should be defined geometrically. This paper relates a definition suggested recently by Cook and Whiting to an older proposal by Matzner, which seems to have been overlooked in the recent literature. It also describes how to calculate approximate Killing fields based on these proposals using an efficient scheme that could be of immediate practical use in numerical relativity.

  14. Killing spinors of some supergravity solutions

    E-print Network

    Daniel Arean

    2006-05-30

    We compute explicitly the Killing spinors of some ten dimensional supergravity solutions. We begin with a 10d metric of the form $\\RR^{1,3}\\times{\\cal Y}_6$, where ${\\cal Y}_6$ is either the singular conifold or any of its resolutions. Then, we move on to the Klebanov-Witten and Klebanov-Tseytlin backgrounds, both constructed over the singular conifold; and we also study the Klebanov-Strassler solution, built over the deformed conifold. Finally, we determine the form of the Killing spinors for the non-commutative deformation of the Maldacena-N\\'u\\~nez geometry.

  15. Killing Spinors for the Bosonic String

    E-print Network

    H. Lu; Zhao-Long Wang

    2011-06-08

    We obtain the effective action for the bosonic string with arbitrary Yang-Mills fields, up to the \\alpha' order, in general dimensions. The form of the action is determined by the requirement that the action admit well-defined Killing spinor equations, whose projected integrability conditions give rise to the full set of equations of motion. The success of the construction suggests that the hidden "pseudo-supersymmetry" associated with the Killing spinor equations may be a property of the bosonic string itself.

  16. HIV transcription is induced with cell killing

    SciTech Connect

    Woloschak, G.E.; Schreck, S.; Chang-Liu, Chin-Mei [Argonne National Lab., IL (United States); Panozzo, J.; Libertin, C.R. [Loyola Univ. Medical Center, Maywood, IL (United States)

    1993-11-01

    In this report, we demonstrate that this induction of HIV-LTR transcription occurs when stably transfected HeLa cells are exposed to agents which mediate cell killing, such as UV radiation, electroporation of sucrose buffer, prolonged heating, and low and high pH. Cells cultured following UV exposure demonstrated a peak in CAT expression that is evident in viable (but not necessarily cell division-competent) cells 24 h after exposure; this inductive response continued until at least 72 h after exposure. HIV-LTR induction was dose-dependent, and the amount of CAT transcription induced was correlated with the amount of cell killing that occurred in the culture.

  17. Internet Resources on Genocide and Mass Killings

    NSDL National Science Digital Library

    Internet Resources on Genocide and Mass Killings is an extensive compilation of primary materials and annotated links related to "twentieth-century genocidal and mass man-made killing occurrences." Divided into fifteen sections, subject coverage includes topics such as The Jewish Holocaust, War Crimes and Criminals, Yugoslavia and Kosovo, among others. Most of the original documents in the compilation have been uploaded to the site, facilitating navigation and research. Documents not residing at the site are linked via succinct annotations. The compilation is searchable and updated continuously by its creator Dr. Stuart D. Stein, Senior Lecturer in Sociology and Social Psychology at the University of West England.

  18. Cytotoxic Killing and Immune Evasion by Repair

    NASA Astrophysics Data System (ADS)

    Chan, Cliburn; George, Andrew J. T.; Stark, Jaroslav

    2007-07-01

    The interaction between the immune system and pathogens is a complex one, with pathogens constantly developing new ways of evading destruction by the immune system. The immune system's task is made even harder when the pathogen in question is an intra-cellular one (such as a virus or certain bacteria) and it is necessary to kill the infected host cell in order to eliminate the pathogen. This causes damage to the host, and such killing therefore needs to be carefully controlled, particularly in tissues with poor regenerative potential, or those involved in the immune response itself. Host cells therefore possess repair mechanisms which can counteract killing by immune cells. These in turn can be subverted by pathogens which up-regulate the resistance of infected cells to killing. In this paper, we explore the hypothesis that this repair process plays an important role in determining the efficacy of evasion and escape from immune control. We model a situation where cytotoxic T lymphocytes (CTL) and natural killer (NK) cells kill pathogen-infected and tumour cells by directed secretion of preformed granules containing perforin and granzymes. Resistance to such killing can be conferred by the expression of serine protease inhibitors (serpins). These are utilized by several virally infected and tumour cells, as well as playing a role in the protection of host bystander, immune and immuneprivileged cells. We build a simple stochastic model of cytotoxic killing, where serpins can neutralize granzymes stoichiometrically by forming an irreversible complex, and the survival of the cell is determined by the balance between serpin depletion and replenishment, which in its simplest form is equivalent to the well known shot noise process. We use existing analytical results for this process, and additional simulations to analyse the effects of repair on cytotoxic killing. We then extend the model to the case of a replicating target cell population, which gives a branching process coupled to shot noise. We show how the process of repair can have a major impact on the dynamics of pathogen evasion and escape of tumour cells from immune surveillance

  19. Mothers who killed or attempted to kill their child: life circumstances, childhood abuse, and types of killing.

    PubMed

    Haapasalo, J; Petäjä, S

    1999-01-01

    The objectives of the present study were to examine the life circumstances, childhood abuse, and types of homicidal acts of 48 mothers who killed/attempted to kill their child(ren) under age 12 between 1970-96 in Finland. Data on the mothers'life stresses, psychological problems, and childhood abuse were collected from mental state examination (MSE) reports. The cases were divided into 15 neonaticides and 33 mothers who killed an older child. Childhood abuse was documented in 63% of the mothers' MSE reports. Qualitative analysis identified neonaticides,joint homicide-suicide attempts, impulsive aggression, psychotic acts, postpartum depression, and abusive acts. Nonlinear principal components analysis showed that different variables were related to the neonaticide and non-neonaticide cases. We concluded that despite differences in the psychosocial profiles of neonaticides and other maternal homicidal acts the cycle of violence perspective can be applied to both cases, even though it may not be a sufficient explanation for maternal child killings. PMID:10606431

  20. Native Birds and Alien Insects: Spatial Density Dependence in Songbird Predation of Invading Oak Gallwasps

    PubMed Central

    Schönrogge, Karsten; Begg, Tracey; Stone, Graham N.

    2013-01-01

    Revealing the interactions between alien species and native communities is central to understanding the ecological consequences of range expansion. Much has been learned through study of the communities developing around invading herbivorous insects. Much less, however, is known about the significance of such aliens for native vertebrate predators for which invaders may represent a novel food source. We quantified spatial patterns in native bird predation of invading gall-inducing Andricus wasps associated with introduced Turkey oak (Quercus cerris) at eight sites across the UK. These gallwasps are available at high density before the emergence of caterpillars that are the principle spring food of native insectivorous birds. Native birds showed positive spatial density dependence in gall attack rates at two sites in southern England, foraging most extensively on trees with highest gall densities. In a subsequent study at one of these sites, positive spatial density dependence persisted through four of five sequential week-long periods of data collection. Both patterns imply that invading galls are a significant resource for at least some native bird populations. Density dependence was strongest in southern UK bird populations that have had longest exposure to the invading gallwasps. We hypothesise that this pattern results from the time taken for native bird populations to learn how to exploit this novel resource. PMID:23342048

  1. Development and clinical application of an InvaderPlus(®) assay for the detection of genital mycoplasmas.

    PubMed

    Takanashi, Masaki; Ito, Shin; Kaneto, Hiroyuki; Tanahashi, Yoshikatsu; Kitanohara, Masataka; Yanagihara, Akira; Nakazima, Haruhiko; Yasuda, Mitsuru

    2015-07-01

    We developed a PCR-based assay involving Invader(®) technology for detection of the genital mycoplasmas of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum. We compared its performance with that of a PCR-microtiter plate hybridization assay, which we developed previously, in detecting genital mycoplasmas in first-voided urine (FVU) specimens from men with non-gonococcal urethritis. The tests targeting each of the genital mycoplasmas were specific for the respective species and could detect as few as 10 copies of the plasmids containing the target genes of each of the genital mycoplasmas per reaction. The assay using the InvaderPlus(®) method (InvaderPlus(®) assay) showed very similar performance to that of the PCR-microtiter plate hybridization assay for detecting the genital mycoplasmas in the FVU specimens. In addition, the PCR and endonuclease reaction in the InvaderPlus(®) assay were carried out simultaneously in one procedure, thus simplifying the assay, leading to time- and labor-savings and a decrease in the risk of specimen contamination. The InvaderPlus(®) assay could be useful in diagnosing genitourinary tract infections caused by the genital mycoplasmas. PMID:25892209

  2. Metabolic activity of microorganisms in evaporites

    NASA Technical Reports Server (NTRS)

    Rothschild, L. J.; Giver, L. J.; White, M. R.; Mancinelli, R. L.

    1994-01-01

    Crystalline salt is generally considered so hostile to most forms of life that it has been used for centuries as a preservative. Here, we present evidence that prokaryotes inhabiting a natural evaporite crust of halite and gypsum are metabolically active while inside the evaporite for at least 10 months. In situ measurements demonstrated that some of these "endoevaporitic" microorganisms (probably the cyanobacterium Synechococcus Nageli) fixed carbon and nitrogen. Denitrification was not observed. Our results quantified the slow microbial activity that can occur in salt crystals. Implications of this study include the possibility that microorganisms found in ancient evaporite deposits may have been part of an evaporite community.

  3. Physiologically anaerobic microorganisms of the deep subsurface

    SciTech Connect

    Stevens, S.E. Jr.; Chung, K.T.

    1991-06-01

    This study seeks to determine numbers, diversity, and morphology of anaerobic microorganisms in 15 samples of subsurface material from the Idaho National Engineering Laboratory, in 18 samples from the Hanford Reservation and in 1 rock sample from the Nevada Test Site; set up long term experiments on the chemical activities of anaerobic microorganisms based on these same samples; work to improve methods for the micro-scale determination of in situ anaerobic microbial activity;and to begin to isolate anaerobes from these samples into axenic culture with identification of the axenic isolates.

  4. Hydrodynamic phase locking of swimming microorganisms.

    PubMed

    Elfring, Gwynn J; Lauga, Eric

    2009-08-21

    Some microorganisms, such as spermatozoa, synchronize their flagella when swimming in close proximity. Using a simplified model (two infinite, parallel, two-dimensional waving sheets), we show that phase locking arises from hydrodynamics forces alone, and has its origin in the front-back asymmetry of the geometry of their flagellar waveform. The time evolution of the phase difference between coswimming cells depends only on the nature of this geometrical asymmetry, and microorganisms can phase lock into conformations which minimize or maximize energy dissipation. PMID:19792766

  5. Hydrodynamic Phase Locking of Swimming Microorganisms

    NASA Astrophysics Data System (ADS)

    Elfring, Gwynn J.; Lauga, Eric

    2009-08-01

    Some microorganisms, such as spermatozoa, synchronize their flagella when swimming in close proximity. Using a simplified model (two infinite, parallel, two-dimensional waving sheets), we show that phase locking arises from hydrodynamics forces alone, and has its origin in the front-back asymmetry of the geometry of their flagellar waveform. The time evolution of the phase difference between coswimming cells depends only on the nature of this geometrical asymmetry, and microorganisms can phase lock into conformations which minimize or maximize energy dissipation.

  6. Inactivation of Microorganisms by Electrohydraulic Shock1

    PubMed Central

    Gilliland, S. E.; Speck, M. L.

    1967-01-01

    The electrohydraulic shock treatment of microorganisms was accomplished by discharging high-voltage electricity (8 to 15 kv) across an electrode gap below the surface of aqueous suspensions of the microorganisms. This treatment was effective in destroying Escherichia coli, Streptococcus faecalis, vegetative cells and spores of Bacillus subtilis, and bacteriophage specific for S. cremoris ML1. The presence of added protein in bacterial suspensions resulted in reduced bactericidal action. Water subjected to electrohydraulic treatment retained a certain amount of toxicity when copper-core electrodes were used to apply the treatment. This was caused by copper liberated from the electrode during electrohydraulic discharge. PMID:4965615

  7. Life history variation in a temperate plant invader, Verbascum thapsus along a tropical elevational gradient in Hawaii

    Microsoft Academic Search

    Shahin AnsariCurtis; Curtis C. Daehler

    2010-01-01

    Few studies have examined the life history of temperate plant invaders in the tropics. Temperate invaders that utilize seasonal\\u000a cues to influence their life histories may be expected to behave differently in the tropics. This study examined variation\\u000a in life history in an invading temperate weed, Verbascum thapsus, across an elevation gradient (1,690–2,720 m) along the montane and subalpine slopes of

  8. killed-virus influenza vaccine Polio vaccine

    E-print Network

    Shyy, Wei

    killed-virus influenza vaccine Polio vaccine FluMist Thomas Francis, Jr. National Institutes of Health live-virus influenza vaccine Hunein Maassab Jonas Salk Type-A virus trivalent cold that Maassab's innovative, trivalent, cold- adapted influenza vaccine, FluMist, which uses live but weakened

  9. How do cytotoxic lymphocytes kill their targets?

    Microsoft Academic Search

    Sujan Shresta; Christine TN Pham; Dori A Thomas; Timothy A Graubert; Timothy J Ley

    1998-01-01

    CD8+ cytotoxic lymphocytes, natural killer cells and lymphokine-activated killer cells depend primarily on the perforin\\/granzyme system to kill their targets, while CD4+ T cells utilize Fas and other mechanisms to induce cell death. The molecular mechanisms used by these pathways to induce target cell apoptosis may converge on common death substrates.

  10. Killing spinors on supersymmetric P-branes

    E-print Network

    Rodrigo Aros; Mauricio Romo

    2007-10-07

    A class of p-brane solutions for supersymmetric gravity theories with negative cosmological constant are proposed and analyzed. The solutions are purely bosonic and contain a worldsheet and a transverse section. The classification relays on the number of intrinsic Killing spinors on the worldsheet and the transverse section. A explicit discussion of the classification is performed for the four dimensional worldsheet case.

  11. School Shootings; Standards Kill Students and Society

    ERIC Educational Resources Information Center

    Angert, Betsy L.

    2008-01-01

    School shootings have been in the news of late. People ponder what occurs in classrooms today. Why would a young person wish to take a life? Within educational institutions, the killings are a concern. In our dire attempt to teach the children and ensure student success, it seems many of our offspring are lost. Some students feel separate from…

  12. Axial Current, Killing Vector and Newtonian Gravity

    E-print Network

    Prasanta Mahato

    2011-02-22

    Starting from the multiplicative torsion approach of gravity and assuming a Killing vector to be proportional to the axial-vector matter current, here we derive Newton's law of gravity where the logarithm of the proportionality factor has been found to be the potential function.

  13. Mass killings and detection of impacts

    NASA Technical Reports Server (NTRS)

    Mclaren, Digby J.

    1988-01-01

    Highly energetic bolide impacts occur and their flux is known. For larger bodies the energy release is greater than for any other short-term global phenomenon. Such impacts produce or release a large variety of shock induced changes including major atmospheric, sedimentologic, seismic and volcanic events. These events must necessarily leave a variety of records in the stratigraphic column, including mass killings resulting in major changes in population density and reduction or extinction of many taxonomic groups, followed by characteristic patterns of faunal and flora replacement. Of these effects, mass killings, marked by large-scale loss of biomass, are the most easily detected evidence in the field but must be manifest on a near-global scale. Such mass killings that appear to be approximately synchronous and involve disappearance of biomass at a bedding plane in many sedimentologically independent sections globally suggest a common cause and probable synchroneity. Mass killings identify an horizon which may be examined for evidence of cause. Geochemical markers may be ephemeral and absence may not be significant. There appears to be no reason why ongoing phenomena such as climate and sea-level changes are primary causes of anomolous episodic events.

  14. Killing Hitler: A Writer's Journey and Angst.

    ERIC Educational Resources Information Center

    Thaler, Paul

    2002-01-01

    Describes the author's experiences in preparing a talk that "evokes the specter" of Adolf Hitler and in writing an historical account of a British plot to kill Hitler. Address the question of why the British allowed him to live that final year of the war. Muses on why scholars write, and the impact of violence and terrorism. (SG)

  15. Advanced gel propulsion controls for kill vehicles

    Microsoft Academic Search

    W. K. Yasuhara; A. Olson; S. Finato

    1993-01-01

    A gel propulsion control concept for tactical applications is reviewed, and the status of the individual component technologies currently under development at the Aerojet Propulsion Division is discussed. It is concluded that a gel propellant Divert and Attitude Control Subsystem (DACS) provides a safe, insensitive munitions compliant alternative to current liquid Theater Missile Defense (TMD) DACS approaches. The gel kill

  16. The Ultimate Buzz Kill Mosquito Control

    E-print Network

    Johnson, Eric E.

    : egg, larva, pupa, and adult. 2. Mosquitoes lay groups of eggs on the surface of water or at the base larvae. Unused swimming pools should be drained and kept dry during the mosquito season. Larval ControlThe Ultimate Buzz Kill Mosquito Control Biology Lesson 1. All mosquitoes pass through 4 life stages

  17. Peanut Roaster Temperatures Relative to Salmonella Kill

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ARS, Market Quality and Handling Research Unit, Raleigh NC 27695 In response to the limited peanut butter contamination incident of 2006/7, studies were initiated to examine the effect of various time and temperature protocols on log kill levels for Salmonella on peanuts. The objective of the work ...

  18. Homothetic Killing Vectors in Expanding HH-Spaces with Lambda

    E-print Network

    Adam Chudecki

    2011-04-18

    Conformal Killing equations and their integrability conditions for expanding hyperheavenly spaces with Lambda in spinorial formalism are studied. It is shown that any conformal Killing vector reduces to homothetic or isometric Killing vector. Reduction of respective Killing equation to one master equation is presented. Classification of homothetic and isometric Killing vectors is given. Type [D]x[any] is analysed in details and some expanding HH complex metrics of types [III, N]x[III, N] with Lambda admitting isometric Killing vectors are found.

  19. Contagion in Mass Killings and School Shootings

    PubMed Central

    Towers, Sherry; Gomez-Lievano, Andres; Khan, Maryam; Mubayi, Anuj; Castillo-Chavez, Carlos

    2015-01-01

    Background Several past studies have found that media reports of suicides and homicides appear to subsequently increase the incidence of similar events in the community, apparently due to the coverage planting the seeds of ideation in at-risk individuals to commit similar acts. Methods Here we explore whether or not contagion is evident in more high-profile incidents, such as school shootings and mass killings (incidents with four or more people killed). We fit a contagion model to recent data sets related to such incidents in the US, with terms that take into account the fact that a school shooting or mass murder may temporarily increase the probability of a similar event in the immediate future, by assuming an exponential decay in contagiousness after an event. Conclusions We find significant evidence that mass killings involving firearms are incented by similar events in the immediate past. On average, this temporary increase in probability lasts 13 days, and each incident incites at least 0.30 new incidents (p = 0.0015). We also find significant evidence of contagion in school shootings, for which an incident is contagious for an average of 13 days, and incites an average of at least 0.22 new incidents (p = 0.0001). All p-values are assessed based on a likelihood ratio test comparing the likelihood of a contagion model to that of a null model with no contagion. On average, mass killings involving firearms occur approximately every two weeks in the US, while school shootings occur on average monthly. We find that state prevalence of firearm ownership is significantly associated with the state incidence of mass killings with firearms, school shootings, and mass shootings. PMID:26135941

  20. Metastatic Breast Cancer Cells Collectively Invade Collagen by Following a Glucose Gradient

    NASA Astrophysics Data System (ADS)

    Sun, Bo; Austin, Robert; Liu, Liyu; Duclos, Guillaume; Lee, Jeongseog; Wu, Amy; Kam, Yooseok; Sontag, Eduardo; Stone, Howard; Sturm, James; Gatenby, Robert

    2013-03-01

    We show that MDA-MB-231 metastatic breast cancer cells collectively invade a three dimensional collagen matrix by following a glucose gradient. We observe that due to the 3D physical deformation of the matrix, as measured by the displacement of reporter beads within the matrix, there exists a long range deformation mechanical field inside the matrix which serves to couple the motions of the invading metastatic cell. The invasion front of the cells is a dynamic one, with different cells assuming the lead on a time scale of 24 hours due to certain cells having higher speeds of penetration, which are not sustained. The front cell leadership is dynamic presumably due to metabolic costs associated with the long range strain field which proceeds the invading cell front, which we have imaged using confocal imaging and marker beads imbedded in the collagen matrix. We show that MDA-MB-231 metastatic breast cancer cells collectively invade a three dimensional collagen matrix by following a glucose gradient. We observe that due to the 3D physical deformation of the matrix, as measured by the displacement of reporter beads within the matrix, there exists a long range deformation mechanical field inside the matrix which serves to couple the motions of the invading metastatic cell. The invasion front of the cells is a dynamic one, with different cells assuming the lead on a time scale of 24 hours due to certain cells having higher speeds of penetration, which are not sustained. The front cell leadership is dynamic presumably due to metabolic costs associated with the long range strain field which proceeds the invading cell front, which we have imaged using confocal imaging and marker beads imbedded in the collagen matrix. Sponsored by the NCI/NIH Physical Sciences Oncology Centers

  1. Microorganism lipid droplets and biofuel development

    PubMed Central

    Liu, Yingmei; Zhang, Congyan; Shen, Xipeng; Zhang, Xuelin; Cichello, Simon; Guan, Hongbin; Liu, Pingsheng

    2013-01-01

    Lipid droplet (LD) is a cellular organelle that stores neutral lipids as a source of energy and carbon. However, recent research has emerged that the organelle is involved in lipid synthesis, transportation, and metabolism, as well as mediating cellular protein storage and degradation. With the exception of multi-cellular organisms, some unicellular microorganisms have been observed to contain LDs. The organelle has been isolated and characterized from numerous organisms. Triacylglycerol (TAG) accumulation in LDs can be in excess of 50% of the dry weight in some microorganisms, and a maximum of 87% in some instances. These microorganisms include eukaryotes such as yeast and green algae as well as prokaryotes such as bacteria. Some organisms obtain carbon from CO2 via photosynthesis, while the majority utilizes carbon from various types of biomass. Therefore, high TAG content generated by utilizing waste or cheap biomass, coupled with an efficient conversion rate, present these organisms as bio-tech ‘factories’ to produce biodiesel. This review summarizes LD research in these organisms and provides useful information for further LD biological research and microorganism biodiesel development. [BMB Reports 2013; 46(12): 575-581] PMID:24355300

  2. Industrial and environmental applications of halophilic microorganisms

    Microsoft Academic Search

    Aharon Oren

    2010-01-01

    In comparison with the thermophilic and the alkaliphilic extremophiles, halophilic microorganisms have as yet found relatively few biotechnological applications. Halophiles are involved in centuries?old processes such as the manufacturing of solar salt from seawater and the production of traditional fermented foods. Two biotechnological processes involving halophiles are highly successful: the production of ??carotene by the green alga Dunaliella and the

  3. PESTICIDE METABOLISM IN PLANTS AND MICROORGANISMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding pesticide metabolism in plants and microorganisms is necessary for pesticide development, safe and efficient use, as well as for developing pesticide bioremediation strategies for contaminated soil and water. Pesticide biotransformation may occur via multi-step processes known as meta...

  4. Radiation sensitivity of hyperthermal composting microorganisms

    NASA Astrophysics Data System (ADS)

    Choi, Jong-Il; Yoon, Min-Chul; Kim, Jae-Hun; Yamashita, Masamichi; Kim, Geun Joong; Lee, Ju-Woon

    In the space station and vehicles designed for long human mission, high-temperature compost is a promising technology for decomposing organic waste and producing the fertilizers. In space, the microorganisms could have the changed biological activities or even be mutated by ionizing irradiation. Therefore, in this study, the effect of gamma irradiation on the sensitivity of bacteria in hyperthermal composting was investigated. The sequence analysis of the amplified 16s rDNA genes and amoA gene were used for the identification of composting microorganisms. Viability of microorganisms in compost soil after gamma irradiation was directly visualized with LIVE/DEAD Baclight viability kit. The dominant bacterial genera are Weissella cibaria and Leuconostoc sp. and fungus genera are Metschnikowia bicuspidate and Pichia guilliermondii, respectively. By the gamma irradiation up to the dose of 1 kGy, the microbial population was not changed. Also, the enzyme activities of amylase and cellulose were sustained by the gamma irradiation. These results show that these hyperthermia microorganisms might have the high resistance to gamma radiation and could be used for agriculture in the Space Station.

  5. HERBICIDE METABOLISM IN PLANTS AND MICROORGANISMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide metabolism in plants and microorganisms is a major factor in the dissipation of these compounds in the environment. Metabolic degradation of herbicides by plant enzymes is the main mechanism of plant resistance of such phytotoxic chemicals. Alternatively, some plant enzymes can metaboliz...

  6. Challenging the political assumption that "Guns don't kill people, crazy people kill people!".

    PubMed

    Hodges, Heath J; Scalora, Mario J

    2015-05-01

    Presumptions that mental illness is causally tied to firearm violence and that guns are too easily acquired by such persons have given rise to laws that categorically restrict people with mental health concerns from exercising a Constitutional right. Underlying these reforms appears to be a revised idiom, "Guns don't kill people-crazy people kill people." The purpose of this commentary is to address these assumptions and provide suggestions for managing this critical threat. (PsycINFO Database Record PMID:25985106

  7. Membrane Fas Ligand Kills Human Peripheral Blood T Lymphocytes, and Soluble Fas Ligand Blocks the Killing

    Microsoft Academic Search

    Takashi Sud; Hideo Hashimoto; Masato Tanaka; Takahiro Ochi; Shigekazu Nagata

    2010-01-01

    Summary It has been believed that the Fas expressed on human peripheral blood T cells (PBT) is non- functional, because these cells are insensitive to agonistic anti-Fas\\/Apo-1 mAbs that efficiently kill in vitro-activated T cells and many Fas-expressing cell lines. Here, we demonstrate that membrane-bound Fas ligand (FasL) kills both fresh and in vitro-activated PBT, indicating that the Fas expressed

  8. Recombinant microorganisms for increased production of organic acids

    SciTech Connect

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

    2013-04-30

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

  9. Recombinant microorganisms for increased production of organic acids

    DOEpatents

    Yi, Jian (East Lansing, MI); Kleff, Susanne (East Lansing, MI); Guettler, Michael V. (Holt, MI)

    2012-02-21

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

  10. 11. GENERAL INTERIOR VIEW OF KILLING FLOOR ON LEVEL 4; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. GENERAL INTERIOR VIEW OF KILLING FLOOR ON LEVEL 4; LOOKING SOUTHWEST TOWARD SPLITTERS' PLATFORMS - Rath Packing Company, Beef Killing Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  11. GOETHALS BRIDGE FROM NORTH SIDE OVER ARTHUR KILL. RAILROAD BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GOETHALS BRIDGE FROM NORTH SIDE OVER ARTHUR KILL. RAILROAD BRIDGE IN FOREGROUND - Goethals Bridge, Spanning Arthur Kill from New Jersey to Staten Island, Staten Island (subdivision), Richmond County, NY

  12. Killing Potentials with Geodesic Gradients on Kahler Surfaces

    E-print Network

    Derdzinski, Andrzej

    Killing Potentials with Geodesic Gradients on K¨ahler Surfaces ANDRZEJ DERDZINSKI ABSTRACT. We classify compact K¨ahler surfaces with nonconstant Killing potentials such that all integral curves of their gradients are reparametrized geodesics. 1. INTRODUCTION Let be a Killing potential on a K¨ahler manifold (M

  13. GENERALIZED KILLING SPINORS ON EINSTEIN MANIFOLDS ANDREI MOROIANU, UWE SEMMELMANN

    E-print Network

    Semmelmann, Uwe

    GENERALIZED KILLING SPINORS ON EINSTEIN MANIFOLDS ANDREI MOROIANU, UWE SEMMELMANN Abstract. We study generalized Killing spinors on compact Einstein manifolds with pos- itive scalar curvature Mathematics Subject Classification: Primary: 53C25, 53C27, 53C40, 83C05 Keywords: generalized Killing spinors

  14. KILLING FORMS ON QUATERNIONKAHLER MANIFOLDS ANDREI MOROIANU AND UWE SEMMELMANN

    E-print Network

    Semmelmann, Uwe

    KILLING FORMS ON QUATERNION­K¨AHLER MANIFOLDS ANDREI MOROIANU AND UWE SEMMELMANN Abstract. We show that every Killing p­form on a compact quaternion­K¨ahler man- ifold has to be parallel for p 2. 2000­locally symmetric Riemannian structures. Recall that twistor (resp. Killing) 1­forms are duals of conformal (resp

  15. GENERALIZED KILLING SPINORS ON EINSTEIN MANIFOLDS ANDREI MOROIANU, UWE SEMMELMANN

    E-print Network

    Semmelmann, Uwe

    GENERALIZED KILLING SPINORS ON EINSTEIN MANIFOLDS ANDREI MOROIANU, UWE SEMMELMANN Abstract. We study generalized Killing spinors on compact Einstein manifolds with posi- tive scalar curvature Mathematics Subject Classification: Primary: 53C25, 53C27, 53C40, 83C05 Keywords: generalized Killing spinors

  16. Killing Vector Fields of Standard Static Space-times

    E-print Network

    Fernando Dobarro; Bulent Unal

    2008-01-30

    We consider Killing vector fields on standard static space-times and obtain equations for a vector field on a standard static space-time to be Killing. We also provide a characterization of Killing vector fields on standard static space-times with compact Riemannian parts.

  17. QUASISTATIONARY DISTRIBUTIONS FOR ONE-DIMENSIONAL DIFFUSIONS WITH KILLING

    E-print Network

    Evans, Steven N.

    QUASISTATIONARY DISTRIBUTIONS FOR ONE-DIMENSIONAL DIFFUSIONS WITH KILLING DAVID STEINSALTZ AND STEVEN N. EVANS Abstract. We extend some results on the convergence of one-dimensional diffusions killed at the boundary, conditioned on extended survival, to the case of general killing on the interior. We show, under

  18. ORIGINAL ARTICLE Nafcillin enhances innate immune-mediated killing

    E-print Network

    Nizet, Victor

    ORIGINAL ARTICLE Nafcillin enhances innate immune-mediated killing of methicillin, and nafcillin in particular, significantly increased killing of S. aureus by selected HDPs from keratinocytes, neutrophils, and platelets. This finding correlated with enhanced killing of MRSA by whole blood, neutrophils

  19. CONFORMAL KILLING SPINORS AND THE HOLONOMY PROBLEM IN LORENTZIAN GEOMETRY

    E-print Network

    Baum, Helga

    CONFORMAL KILLING SPINORS AND THE HOLONOMY PROBLEM IN LORENTZIAN GEOMETRY ­ A SURVEY OF NEW RESULTS ­ HELGA BAUM Abstract. This paper is a survey of recent results about conformal Killing spinors will focus on a special class of geometries admitting conformal Killing spinors ­ on Brinkmann spaces

  20. CONFORMAL KILLING SPINORS AND THE HOLONOMY PROBLEM IN LORENTZIAN GEOMETRY

    E-print Network

    Baum, Helga

    CONFORMAL KILLING SPINORS AND THE HOLONOMY PROBLEM IN LORENTZIAN GEOMETRY -- A SURVEY OF NEW RESULTS -- HELGA BAUM # Abstract. This paper is a survey of recent results about conformal Killing spinors will focus on a special class of geometries admitting conformal Killing spinors -- on Brinkmann spaces

  1. Classification of spacetimes according to conformal Killing vectors

    E-print Network

    K. Saifullah

    2008-10-17

    Conformal Killing vectors (CKVs) preserve the spacetime metric up to a factor. Homothetic vectors and Killing vectors are special cases of CKVs. Classification of some classes of spacetimes on the basis of CKVs give interesting results showing how homothetic and Killing vectors which form subsets of the set of CKVs can be recovered as a result of the above classification.

  2. Parallel and Killing Spinors on Spinc Andrei Moroianu1

    E-print Network

    Paris-Sud XI, Université de

    Parallel and Killing Spinors on Spinc Manifolds Andrei Moroianu1 Institut f¨ur reine Mathematik simply connected Spinc manifolds carrying parallel and real Killing spinors. In particular we show that every Sasakian manifold (not necessarily Einstein) carries a canonical Spinc structure with Killing

  3. ON CONFORMAL KILLING SYMMETRIC TENSOR FIELDS ON RIEMANNIAN MANIFOLDS

    E-print Network

    Sharafutdinov, Vladimir

    ON CONFORMAL KILLING SYMMETRIC TENSOR FIELDS ON RIEMANNIAN MANIFOLDS N. S. DAIRBEKOV AND V. A. SHARAFUTDINOV Abstract. A vector field on a Riemannian manifold is called conformal Killing if it gen- erates one-parameter group of conformal transformation. The class of conformal Killing symmetric tensor

  4. Killing forms on Quaternion-Kahler manifolds Corrigendum

    E-print Network

    Paris-Sud XI, Université de

    Killing forms on Quaternion-K¨ahler manifolds ­ Corrigendum ­ Andrei Moroianu and Uwe Semmelmann The aim of this note is to fill a gap in the proof of Theorem 6.1 in [1] - stating that every Killing p is essential. For m = 1, the quaternionic projective space HP1 S4 carries non-parallel Killing 2-forms and 3

  5. Conformal Killing forms on Riemannian manifolds Uwe Semmelmann

    E-print Network

    Semmelmann, Uwe

    Conformal Killing forms on Riemannian manifolds Uwe Semmelmann February 19, 2012 Abstract Conformal Killing forms are a natural generalization of conformal vector fields on Riemannian manifolds the existence of conformal Killing forms on nearly K¨ahler and weak G2-manifolds. Moreover, we give a complete

  6. KILLING FORMS ON QUATERNIONKAHLER MANIFOLDS ANDREI MOROIANU AND UWE SEMMELMANN

    E-print Network

    Paris-Sud XI, Université de

    KILLING FORMS ON QUATERNION­K¨AHLER MANIFOLDS ANDREI MOROIANU AND UWE SEMMELMANN Abstract. We show that every Killing p­form on a compact quaternion­K¨ahler man- ifold has to be parallel for p 2. 2000­locally symmetric Riemannian structures. Recall that twistor (resp. Killing) 1­forms are duals of conformal (resp

  7. Conformal Killing symmetric tensor fields on a Riemannian manifold

    E-print Network

    Sharafutdinov, Vladimir

    Conformal Killing symmetric tensor fields on a Riemannian manifold Vladimir Sharafutdinov Sobolev Abstract A conformal Killing vector field on a Riemannian manifold is a vector field generating a one-parameter group of conformal transformations. We generalize the differential equation of conformal Killing vector

  8. Inhomogeneous problems Q. How do you kill a blue elephant?

    E-print Network

    DeTurck, Dennis

    Inhomogeneous problems Q. How do you kill a blue elephant? A. With a blue elephant gun Q. How do you kill a pink elephant? A. Squeeze its trunk until it turns blue, and then shoot it with a blue elephant gun. Q. How do you kill a white elephant? A. Tickle it pink, then squeeze its trunk until it turns

  9. It's not just conflict that motivates killing of orangutans.

    PubMed

    Davis, Jacqueline T; Mengersen, Kerrie; Abram, Nicola K; Ancrenaz, Marc; Wells, Jessie A; Meijaard, Erik

    2013-01-01

    We investigated why orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill orangutans. Those who reported having personally killed an orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons orangutans were killed was fear of orangutans or in self-defence. A similar pattern was evident among reports of orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 orangutans were killed in Kalimantan within the respondents' active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI) and between 26,361 and 41,688 for non-conflict reasons (95% CI). These findings confirm that habitat protection alone will not ensure the survival of orangutans in Indonesian Borneo, and that effective reduction of orangutan killings is urgently needed. PMID:24130707

  10. Potential Theory of Special Subordinators and Subordinate Killed Stable Processes

    E-print Network

    Vondraèek, Zoran

    Potential Theory of Special Subordinators and Subordinate Killed Stable Processes Renming Song their potential theory. Then we study the potential theory of processes obtained by subordinating a killed-to-one correspondence between the nonnegative harmonic functions of the killed symmetric stable process and the non

  11. Tools and Technology Article Methods for Locating African Lion Kills

    E-print Network

    Getz, Wayne M.

    Tools and Technology Article Methods for Locating African Lion Kills Using Global Positioning. Identification of large carnivore kill sites using Global Positioning System (GPS) data is gaining popularity. We (Panthera leo) kill sites from 1,477 investigated GPS clusters. Ratio of distance moved 24 hours before

  12. Structural equations for Killing tensors of arbitrary rank* Thomas Wolf

    E-print Network

    Wolf, Thomas

    Structural equations for Killing tensors of arbitrary rankABFB. The FA are the components of a Killing tensor Ki1...irof arbitrary rank r * *and its symmetrized numerically the number of non-trivial Killing tensors using n* *umerical values for the Riemann tensor

  13. 138 RestoRative Commons Fresh Kills site; an aerial

    E-print Network

    138 RestoRative Commons Fresh Kills site; an aerial view, looking north. IMAGE usEd wIth p New York City Department of City Planning Fresh Kills Park, Staten Island, NY The rehabilitation for--or has substantive involvement in--the redevelopment. A project such as the making of Fresh Kills

  14. Road-Killed Animals as Resources for Ecological Studies.

    ERIC Educational Resources Information Center

    Adams, Clark E.

    1983-01-01

    Summarizes 19 literature sources identifying road-killed vertebrates and frequency of kill by numbers. Examples of how these animals can be incorporated into curricula (integrating biology, society, people, and values) are given, followed by an illustrated example of how a road-killed raccoon's skull demonstrated a human/wildlife interaction prior…

  15. Antimicrobial Photodynamic Therapy to Kill Gram-negative Bacteria

    PubMed Central

    Sperandio, Felipe F; Huang, Ying-Ying; Hamblin, Michael R

    2013-01-01

    Antimicrobial photodynamic therapy (PDT) or photodynamic inactivation (PDI) is a new promising strategy to eradicate pathogenic microorganisms such as Gram-positive and Gram-negative bacteria, yeasts and fungi. The search for new approaches that can kill bacteria but do not induce the appearance of undesired drug-resistant strains suggests that PDT may have advantages over traditional antibiotic therapy. PDT is a non-thermal photochemical reaction that involves the simultaneous presence of visible light, oxygen and a dye or photosensitizer (PS). Several PS have been studied for their ability to bind to bacteria and efficiently generate reactive oxygen species (ROS) upon photostimulation. ROS are formed through type I or II mechanisms and may inactivate several classes of microbial cells including Gram-negative bacteria such as Pseudomonas aeruginosa, which are typically characterized by an impermeable outer cell membrane that contains endotoxins and blocks antibiotics, dyes, and detergents, protecting the sensitive inner membrane and cell wall. This review covers significant peer-reviewed articles together with US and World patents that were filed within the past few years and that relate to the eradication of Gram-negative bacteria via PDI or PDT. It is organized mainly according to the nature of the PS involved and includes natural or synthetic food dyes; cationic dyes such as methylene blue and toluidine blue; tetrapyrrole derivatives such as phthalocyanines, chlorins, porphyrins, chlorophyll and bacteriochlorophyll derivatives; functionalized fullerenes; nanoparticles combined with different PS; other formulations designed to target PS to bacteria; photoactive materials and surfaces; conjugates between PS and polycationic polymers or antibodies; and permeabilizing agents such as EDTA, PMNP and CaCl2. The present review also covers the different laboratory animal models normally used to treat Gram-negative bacterial infections with antimicrobial PDT. PMID:23550545

  16. Conformal killing tensors and covariant Hamiltonian dynamics

    NASA Astrophysics Data System (ADS)

    Cariglia, M.; Gibbons, G. W.; van Holten, J.-W.; Horvathy, P. A.; Zhang, P.-M.

    2014-12-01

    A covariant algorithm for deriving the conserved quantities for natural Hamiltonian systems is combined with the non-relativistic framework of Eisenhart, and of Duval, in which the classical trajectories arise as geodesics in a higher dimensional space-time, realized by Brinkmann manifolds. Conserved quantities which are polynomial in the momenta can be built using time-dependent conformal Killing tensors with flux. The latter are associated with terms proportional to the Hamiltonian in the lower dimensional theory and with spectrum generating algebras for higher dimensional quantities of order 1 and 2 in the momenta. Illustrations of the general theory include the Runge-Lenz vector for planetary motion with a time-dependent gravitational constant G(t), motion in a time-dependent electromagnetic field of a certain form, quantum dots, the Hénon-Heiles and Holt systems, respectively, providing us with Killing tensors of rank that ranges from one to six.

  17. Conformal Killing Tensors and covariant Hamiltonian Dynamics

    E-print Network

    M. Cariglia; G. W. Gibbons; J. -W. van Holten; P. A. Horvathy; P. -M. Zhang

    2014-10-31

    A covariant algorithm for deriving the conserved quantities for natural Hamiltonian systems is combined with the non-relativistic framework of Eisenhart, and of Duval, in which the classical trajectories arise as geodesics in a higher dimensional space-time, realized by Brinkmann manifolds. Conserved quantities which are polynomial in the momenta can be built using time-dependent conformal Killing tensors with flux. The latter are associated with terms proportional to the Hamiltonian in the lower dimensional theory and with spectrum generating algebras for higher dimensional quantities of order $1$ and $2$ in the momenta. Illustrations of the general theory include the Runge-Lenz vector for planetary motion with a time-dependent gravitational constant $G(t)$, motion in a time-dependent electromagnetic field of a certain form, quantum dots, the H\\'enon-Heiles and Holt systems, respectively, providing us with Killing tensors of rank that ranges from one to six.

  18. Downregulation of major histocompatibility complex antigens in invading glioma cells: stealth invasion of the brain

    Microsoft Academic Search

    David Zagzag; Konstantin Salnikow; Luis Chiriboga; Herman Yee; Li Lan; M Aktar Ali; Roberto Garcia; Sandra Demaria; Elizabeth W Newcomb

    2005-01-01

    Invasion into surrounding brain tissue is a fundamental feature of gliomas and the major reason for treatment failure. The process of brain invasion in gliomas is not well understood. Differences in gene expression and\\/or gene products between invading and noninvading glioma cells may identify potential targets for new therapies. To look for genes associated with glioma invasion, we first employed

  19. Mycobacterium avium Invades the Intestinal Mucosa Primarily by Interacting with Enterocytes

    Microsoft Academic Search

    FELIX J. SANGARI; JOSEPH GOODMAN; MARY PETROFSKY; PETER KOLONOSKI; LUIZ E. BERMUDEZ

    2001-01-01

    Previous studies have demonstrated that Mycobacterium avium can invade intestinal epithelial cells both in vitro and in vivo. When given to mice orally, M. avium preferentially interacts with the intestinal mucosa at the terminal ileum. We evaluated the mechanism(s) of M. avium binding and invasion of the intestinal mucosa using three different systems: (i) electron microscopy following administration of M.

  20. A complex relationship: the interaction among symbiotic microbes, invading pathogens, and their mammalian host

    Microsoft Academic Search

    M M Curtis; V Sperandio

    2011-01-01

    Symbiosis between microbes and their mammalian host is vital to maintaining homeostasis. Symbiotic microbes within the gastrointestinal tract provide an array of benefits to the host, including promotion of host immunity. A coordinated effort of the host and symbiotic microbes deters the colonization and survival of many invading pathogens. However, pathogens have devised strategies to overcome these mechanisms. Furthermore, some

  1. Impact of Alien Plant Invaders on Pollination Networks in Two Archipelagos

    PubMed Central

    Padrón, Benigno; Traveset, Anna; Biedenweg, Tine; Díaz, Diana; Nogales, Manuel; Olesen, Jens M.

    2009-01-01

    Mutualistic interactions between plants and animals promote integration of invasive species into native communities. In turn, the integrated invaders may alter existing patterns of mutualistic interactions. Here we simultaneously map in detail effects of invaders on parameters describing the topology of both plant-pollinator (bi-modal) and plant-plant (uni-modal) networks. We focus on the invader Opuntia spp., a cosmopolitan alien cactus. We compare two island systems: Tenerife (Canary Islands) and Menorca (Balearic Islands). Opuntia was found to modify the number of links between plants and pollinators, and was integrated into the new communities via the most generalist pollinators, but did not affect the general network pattern. The plant uni-modal networks showed disassortative linkage, i.e. species with many links tended to connect to species with few links. Thus, by linking to generalist natives, Opuntia remained peripheral to network topology, and this is probably why native network properties were not affected at least in one of the islands. We conclude that the network analytical approach is indeed a valuable tool to evaluate the effect of invaders on native communities. PMID:19609437

  2. For the past 26 years, robots have invaded Caltech each spring to battle for their makers'

    E-print Network

    For the past 26 years, robots have invaded Caltech each spring to battle for their makers' bragging teams of undergrads competed in an "extreme recy- cling" challenge that pitted pairs of robotic vehicles against difficult terrain and other robots in an effort to collect plastic water bottles, aluminum cans

  3. Differential influence of Pomphorhynchus laevis (Acanthocephala) on the behaviour of native and invader gammarid species

    Microsoft Academic Search

    Alexandre Bauer; Sandrine Trouvé; Arnaud Grégoire; Frank Cézilly

    2000-01-01

    Although various species of acanthocephalan parasites can increase the vulnerability of their amphipod intermediate hosts to predation, particularly by altering their photophobic behaviour, their influence on the structure of amphipod communities and the success of invader species has so far received little attention. We compared the prevalence and behavioural influence of a fish acanthocephalan parasite, Pomphorhynchus laevis, in two species

  4. Effects of native species diversity and resource additions on invader impact.

    PubMed

    Maron, John L; Marler, Marilyn

    2008-07-01

    Theory and empirical work have demonstrated that diverse communities can inhibit invasion. Yet, it is unclear how diversity influences invader impact, how impact varies among exotics, and what the relative importance of diversity is versus extrinsic factors that themselves can influence invasion. To address these issues, we established plant assemblages that varied in native species and functional richness and crossed this gradient in diversity with resource (water) addition. Identical assemblages were either uninvaded or invaded with one of three exotic forbs: spotted knapweed (Centaurea maculosa), dalmatian toadflax (Linaria dalmatica), or sulfur cinquefoil (Potentilla recta). To determine impacts, we measured the effects of exotics on native biomass and, for spotted knapweed, on soil moisture and nitrogen levels. Assemblages with high species richness were less invaded and less impacted than less diverse assemblages. Impact scaled with exotic biomass; spotted knapweed had the largest impact on native biomass compared with the other exotics. Although invasion depressed native biomass, the net result was to increase total community yield. Water addition increased invasibility (for knapweed only) but had no effect on invader impact. Together, these results suggest that diversity inhibits invasion and reduces impact more than resource additions facilitate invasion or impact. PMID:18554141

  5. I smell an invasive invader: Using portable gas spectrometry at ports of entry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inspectors at ports of entry are faced with the daunting task of finding a visual sign of a pest or disease. Small insects, pests concealed inside plant material and plant diseases could escape detection and invade the country. In a collaborative effort, portable gas chromatography technology was te...

  6. Dispersal and demography contributions to population spread of Carduus nutans in its native and invaded ranges

    Microsoft Academic Search

    Eelke Jongejans; Katriona Shea; Olav Skarpaas; Dave Kelly; Andy W. Sheppard; Tim L. Woodburn

    2008-01-01

    Summary 1. Invasive species usually exhibit different spatial population dynamics in their native and invaded range. This is often attributed to demographic differences, but may be due to differences in dispersal as well. 2. Regardless of how these dispersal and demographic differences from the native range arose, studying how they contributed to increases in population spread rates will increase our

  7. Host stage preference, efficacy and fecundity of parasitoids attacking Drosophila suzukii in newly invaded areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is an invasive species, native to Eastern and Southeastern Asia, that has recently colonized parts of North America and Europe. The severe damage caused by D. suzukii in the newly invaded areas is largely due to the absence of specialized natur...

  8. Ants are among the most prevalent pests in households. Ants also invade restau-

    E-print Network

    Ishida, Yuko

    Ants are among the most prevalent pests in households. Ants also invade restau- rants, hospitals indoor plants, ants protect and care for honeydew-producing insects such as aphids, soft scales, whiteflies, and mealy- bugs, increasing damage from these pests. Ants also perform many useful functions

  9. Recovery Potential of Dune Ecosystems Invaded by an Exotic Acacia Species (Acacia longifolia) 1

    Microsoft Academic Search

    HÉLIA S. MARCHANTE; ELIZABETE M. MARCHANTE; ERIKA BUSCARDO; JOSÉ MAIA; HELENA FREITAS

    2004-01-01

    The effect of mechanical clearing and litter removal on control of Sydney golden wattle was studied in areas of Portugal that had been invaded for either long or short periods. The plant species that emerged and soil parameters were monitored to assess the recovery potential and the soil status of these areas after Sydney golden wattle control. More plant species

  10. The Tertiary FAWAG Process on Gas and Water Invaded Zones: An Experimental Study

    Microsoft Academic Search

    A. Gandomkar; R. Kharrat

    2012-01-01

    In this research, experimental investigations of foam-assisted water alternating gas and water alternating gas processes in carbonate cores are studied in order to estimate the increases in the oil recovery in the gas and water invaded zones. Core flooding experiments were performed for low-temperature fractured carbonate cores, chosen from one of the Iranian carbonate oil reservoirs, under tertiary recovery conditions.

  11. Root-invading fungi of milk vetch on the Loess Plateau, China

    Microsoft Academic Search

    Yali Yin; Z. B. Nan; Chunjie Li; Fujiang Hou

    2008-01-01

    Root-invading fungi of milk vetch (Astragalus adsurgens) at different growth stages grown in three ages of sown pasture soil were studied in Huanxian county, Gansu province, China. Pathogenicity was tested by seed and soil inoculation. A total of 44 fungi were isolated from milk vetch roots, 32 from the roots of field plants and 37 from the roots of potted

  12. Habitat shift in invading species: Zebra and quagga mussel population characteristics on shallow soft substrates

    USGS Publications Warehouse

    Berkman, P.A.; Garton, D.W.; Haltuch, M.A.; Kennedy, G.W.; Febo, L.R.

    2000-01-01

    Unexpected habitat innovations among invading species are illustrated by the expansion of dreissenid mussels across sedimentary environments in shallow water unlike the hard substrates where they are conventionally known. In this note, records of population characteristics of invading zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussels from 1994 through 1998 are reported from shallow (less than 20 m) sedimentary habitats in western Lake Erie. Haphazard SCUBA collections of these invading species indicated that combined densities of zebra and quagga mussels ranged from 0 to 32,500 individuals per square meter between 1994 and 1998, with D. polymorpha comprising 75-100% of the assemblages. These mixed mussel populations, which were attached by byssal threads to each other and underlying sand-grain sediments, had size-frequency distributions that were typical of colonizing populations on hard substrates. Moreover, the presence of two mussel cohorts within the 1994 samples indicated that these species began expanding onto soft substrates not later than 1992, within 4 years of their initial invasion in western Lake Erie. Such historical data provide baselines for interpreting adaptive innovations, ecological interactions and habitat shifts among the two invading dreissenid mussel species in North America.

  13. Behavioral correlations provide a mechanism for explaining high invader densities and increased impacts on native prey.

    PubMed

    Pintor, Lauren M; Sih, Andrew; Kerby, Jacob L

    2009-03-01

    The fact that superabundant invasive pests are also sometimes highly aggressive represents an interesting paradox. Strong intraspecific aggression should result in high intraspecific competition and limit the densities reached by exotic species. One mechanism that can allow invaders to attain high densities despite high intraspecific aggression, involves positive correlations between aggression and other behaviors such as foraging activity. We conducted a mesocosm experiment to quantify the ecological implications of correlations between aggressiveness and foraging activity among groups of exotic signal crayfish (Pacifastacus leniusculus) at low and high densities. Our results showed that high invader densities increased intraspecific aggression and per capita interactions between crayfish, but also increased foraging activity and impacts on preferred prey. As a result, exotic crayfish did not show density-dependent reductions in per capita feeding or growth rates. We suggest that the positive correlation between aggression and activity is part of an aggression syndrome whereby some individuals are generally more aggressive/active than others across situations. An aggression syndrome can couple aggressive behaviors important to population establishment of invasive species with foraging activity that enhances the ability of invaders to attain high densities and have large impacts on invaded communities. PMID:19341130

  14. HOUSEHOLD AND STRUCTURAL INSECTS Impacts of Residual Insecticide Barriers on Perimeter-Invading Ants,

    E-print Network

    Ginzel, Matthew

    liquid insecticide formulations were evaluated as barrier treatments against perimeter-invading ants nonrepellent and repellent liquid insecticides as perimeter treatments for pest ants. In addition, our Þndings that are undergoing apparent range expan- sions (Hedges 2000). Two major invasive ant species are the Argentine ant

  15. Ecology and management of Sheoak (Casuarina spp.), an invader of coastal Florida, U.S.A.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Casuarina spp. are invasive weeds in Florida that threaten biological diversity and beach integrity of coastal habitats. The trees include three species and their hybrids that aggressively invade riverine and coastal areas. Of the three species, C. equisetifolia and C. glauca are highly salt tol...

  16. Genetic cryptic species as biological invaders: the case of a Lessepsian fish migrant,

    E-print Network

    Bernardi, Giacomo

    that are invading the Mediterranean from the Red Sea via the Suez Canal. We PCR amplified and sequenced. The opening of the Suez Canal in 1869, connecting the tropical Red Sea to the subtropical waters the opening of the Suez Canal (Tillier, 1902). It is a small inshore pelagic species, with a very wide

  17. Passive restoration potential of riparian areas invaded by giant reed (Arundo donax) in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed (Arundo donax L.) is a rhizomatous woody non-native grass that has invaded much of the riparian areas of the southwest. By forming thick impenetrable swaths along riverbanks and waterways, giant reed has driven riparian ecosystem decline and displaced native biodiversity. It’s document...

  18. "Invented Invaders": An Engaging Activity to Teach Characteristics Control of Invasive Species

    ERIC Educational Resources Information Center

    Lampert, Evan

    2015-01-01

    Invasive species, defined as exotic species that reach pest status, are major threats to global biodiversity. Although invasive species can belong to any taxonomic group, general characteristics such as rapid growth and reproduction are shared by many invasive species. "Invented Invaders" is a collaborative activity in which students…

  19. Here's to the Losers: Evolvable Residents Accelerate the Evolution of High-Fitness Invaders.

    PubMed

    Gifford, Danna R; Toll-Riera, Macarena; Kojadinovic, Mila; MacLean, R Craig

    2015-07-01

    Recent work has shown that evolvability plays a key role in determining the long-term population dynamics of asexual clones. However, simple considerations suggest that the evolvability of a focal lineage of bacteria should also be influenced by the evolvability of its competitors. First, evolvable competitors should accelerate evolution by impeding the fixation of the focal lineage through a clonal interference-like mechanism. Second, evolvable competitors should increase the strength of selection by rapidly degrading the environment, increasing selection for adaptive mutations. Here we tested these ideas by allowing a high-fitness clone of the bacterium Pseudomonas aeruginosa to invade populations of two low-fitness resident clones that differ in their evolvability. Both competition from mutations in the resident lineage and environmental degradation lead to faster adaptation in the invader through fixing single mutations with a greater fitness advantage. The results suggest that competition from mutations in both the successful invader and the unsuccessful resident shapes the adaptive trajectory of the invader through both direct competition and indirect environmental effects. Therefore, to predict evolutionary outcomes, it will be necessary to consider the evolvability of all members of the community and the effects of adaptation on the quality of the environment. This is particularly relevant to mixed microbial communities where lineages differ in their adaptive potential, a common feature of chronic infections. PMID:26098337

  20. Hepatocellular Carcinoma Invading the Main Portal Vein: Treatment with Transcatheter Arterial Chemoembolization and Portal Vein Stenting

    Microsoft Academic Search

    Zhang Xuebin; Wang Jianhua; Yan Zhiping; Qian Sheng; Liu Rong

    2009-01-01

    To retrospectively analyze the therapeutic results of percutaneous transhepatic portal vein stenting (PTPVS) and transcatheter arterial chemoembolization (TACE) treatment in 58 patients with hepatocellular carcinoma (HCC) invading the main portal vein (MPV). A total of 58 procedures of PTPVS were performed, immediately after which TACE was undertaken to control HCC. The clinical effects, complications, digital subtraction angiographic appearance, stent patency

  1. Can HIV invade a population which is already sick? Rinaldo B. Schinazi

    E-print Network

    Schinazi, Rinaldo

    Can HIV invade a population which is already sick? Rinaldo B. Schinazi University of Colorado and Universit´e de Provence email: schinazi@math.uccs.edu Abstract. It is known that an HIV infection when concomitant with another disease such as tuberculosis or pneumonia is a lot more lethal than HIV alone. We

  2. Comparison of entomofauna between native and medusahead-invaded habitats in northeastern California and northwestern Nevada

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Medusahead (Taeniatherum caput-medusae) is a weedy grass species that has invaded large tracts of open rangeland in the western USA. Medusahead is unpalatable to livestock, reducing forage value of land, and duff from dead, matted medusahead plants increases the frequency and intensity of wildfire,...

  3. A generic risk-based surveying method for invading plant pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive plant pathogens are increasing with international trade and travel with damaging environmental and economic consequences. Recent examples include tree diseases such as Sudden Oak Death in the Western US and Ash Dieback in Europe. To control an invading pathogen it is crucial that newly in...

  4. Posted on Sat, Jun. 19, 2010 Oil plumes invade a dark, mysterious world at Gulf's

    E-print Network

    Belogay, Eugene A.

    of the Deepwater Horizon rig explosion. ``Unfortunately, there's really no place for this oil to go where it wonPosted on Sat, Jun. 19, 2010 Oil plumes invade a dark, mysterious world at Gulf's floor BY ANDRES surprisingly abundant in otherworldly forms of life, much of it fed by gases and oil that seep out of fissures

  5. Optimal Public Control of Exotic Species: Preventing the Brown Tree Snake from Invading Hawai'i

    Microsoft Academic Search

    Brooks Kaiser; James Roumasset

    This paper develops a theoretical model for the efficient establishment of economic policy pertaining to invasive species, integrating prevention and control of invasive species into a single model of optimal control policy, and applies this model to the case of the Brown tree snake as a potential invader of Hawaii. The arrival of a new species to an existing ecosystem

  6. Streptococcus pneumoniae Invades Erythrocytes and Utilizes Them to Evade Human Innate Immunity

    E-print Network

    Nizet, Victor

    Streptococcus pneumoniae Invades Erythrocytes and Utilizes Them to Evade Human Innate Immunity such as pneumonia and sepsis. In blood, erythrocytes are considered to be an important factor for bacterial growth, as they contain abundant nutrients. However, the relationship between S. pneumoniae and erythrocytes remains

  7. Perennial grass dominance: creating a resilient plant community in an exotic annual grass invaded rangeland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Millions of hectares of western rangelands have been invaded by the exotic and invasive annual grass, cheatgrass (Bromus tectorum). Cheatgrass provides a fine-textured, early maturing fuel that has increased the chance, rate, spread and season of wildfire to public and private lands throughout the ...

  8. Impact: toward a framework for understanding the ecological effects of invaders

    Microsoft Academic Search

    I. M. Parker; D. Simberloff; W. M. Lonsdale; K. Goodell; M. Wonham; P. M. Kareiva; M. H. Williamson; B. Von Holle; P. B. Moyle; J. E. Byers; L. Goldwasser

    1999-01-01

    Although ecologists commonly talk about the impacts of nonindigenous species, little formal attention has been given to defining what we mean by impact, or connecting ecological theory with particular measures of impact. The resulting lack of generalizations regarding invasion impacts is more than an academic problem; we need to be able to distinguish invaders with minor effects from those with

  9. Community impacts of anthropogenic disturbance: natural enemies exploit multiple routes in pursuit of invading herbivore hosts

    Microsoft Academic Search

    James A Nicholls; Pablo Fuentes-Utrilla; Alexander Hayward; George Melika; György Csóka; José-Luis Nieves-Aldrey; Juli Pujade-Villar; Majid Tavakoli; Karsten Schönrogge; Graham N Stone

    2010-01-01

    BACKGROUND: Biological invasions provide a window on the process of community assembly. In particular, tracking natural enemy recruitment to invading hosts can reveal the relative roles of co-evolution (including local adaptation) and ecological sorting. We use molecular data to examine colonisation of northern Europe by the parasitoid Megastigmus stigmatizans following invasions of its herbivorous oak gallwasp hosts from the Balkans.

  10. Are interactions among Ponto-Caspian invaders driving amphipod species replacement in the St. Lawrence River?

    Microsoft Academic Search

    Åsa Kestrup; Anthony Ricciardi

    2009-01-01

    In Lake Erie and Lake Ontario, the Ponto-Caspian amphipod Echinogammarus ischnus has replaced the native amphipod Gammarus fasciatus on rocky substrates colonized by dreissenid mussels, which provide interstitial refugia for small invertebrates. Based on the premise that an invader's vulnerability to predation is influenced by its evolutionary experience with the predator and its ability to compete for refugia, we hypothesized

  11. Death receptor-induced cell killing

    Microsoft Academic Search

    Andrew Thorburn

    2004-01-01

    Apoptosis pathways activated by death receptors of the tumour necrosis factor (TNF) family such as Fas, TNFR1, or the TRAIL receptors DR4 and DR5 are implicated in diverse diseases. These are also the best-understood apoptosis pathways and many of our ideas about apoptosis regulation come from studying these pathways. Cell killing from such receptors occurs because of recruitment to the

  12. HIV transcription is induced with cell killing

    Microsoft Academic Search

    G. E. Woloschak; S. Schreck; Chin-Mei Chang-Liu; J. Panozzo; C. R. Libertin

    1993-01-01

    In this report, we demonstrate that this induction of HIV-LTR transcription occurs when stably transfected HeLa cells are exposed to agents which mediate cell killing, such as UV radiation, electroporation of sucrose buffer, prolonged heating, and low and high pH. Cells cultured following UV exposure demonstrated a peak in CAT expression that is evident in viable (but not necessarily cell

  13. AN INTRODUCTION TO FARMER'S BEST FRIENDS - SOIL MICROORGANISMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil microorganisms are essential to life, and to all agricultural practices. They are numerous, diverse, and metabolically flexible. Basic information regarding the soil microorganisms and their roles with respect to crop production are summarized for the layman....

  14. ESTIMATING MICROORGANISM DENSITIES IN AEROSOLS FROM SPRAY IRRIGATION OF WASTEWATER

    EPA Science Inventory

    This document summarizes current knowledge about estimating the density of microorganisms in the air near wastewater management facilities, with emphasis on spray irrigation sites. One technique for modeling microorganism density in air is provided and an aerosol density estimati...

  15. Investigation to identify paint coatings resistive to microorganism growth

    NASA Technical Reports Server (NTRS)

    Cooper, C. W.; Kemp, H. T.

    1971-01-01

    All selected coatings contain nutrients that support microbial growth and survival. Incorporation of microbiocidal agents into coatings more susceptible to attack is recommended for improved inhibition of microorganism growth and for increased protection against deterioration of coatings by microorganisms.

  16. Prey selection of a shell-invading leech as predicted by optimal foraging theory with consumption success

    E-print Network

    Wisenden, Brian D.

    Prey selection of a shell-invading leech as predicted by optimal foraging theory with consumption-invading leech with highly variable consumption success in different prey. Five snail species, including three exhibits prey-size selection. Leeches consumed more med- ium-sized snails among operculated species

  17. Geometry of Killing spinors in neutral signature

    E-print Network

    Dietmar Klemm; Masato Nozawa

    2015-04-21

    We classify the supersymmetric solutions of minimal $N=2$ gauged supergravity in four dimensions with neutral signature. They are distinguished according to the sign of the cosmological constant and whether the vector field constructed as a bilinear of the Killing spinor is null or non-null. In neutral signature the bilinear vector field can be spacelike, which is a new feature not arising in Lorentzian signature. In the $\\LambdaKilling field, which is reminiscent of an Einstein-Weyl structure. If, moreover, the electromagnetic field strength is self-dual, one gets the Kleinian signature analogue of the Przanowski-Tod class of metrics, namely a pseudo-hermitian spacetime determined by solutions of the continuous Toda equation, conformal to a scalar-flat pseudo-K\\"ahler manifold, and admitting in addition a charged conformal Killing spinor. In the $\\Lambda0$ non-null case, the manifold is a fibration over a Lorentzian Gauduchon-Tod base space. Finally, in the $\\Lambda>0$ null class, the metric is contained in the Kundt family, and it turns out that the holonomy is reduced to ${\\rm Sim}(1)\\times{\\rm Sim}(1)$. There appear no self-dual solutions in the null class for either sign of the cosmological constant.

  18. HIV transcription is induced with cell killing

    SciTech Connect

    Woloschak, G.E.; Schreck, S.; Chang-Liu, Chin Mei [Argonne National Lab., IL (United States); Panozzo, J. [Loyola Univ. Medical Center, Maywood, IL (United States). Dept. of Pathology; Libertin, C.R. [Loyola Univ. Medical Center, Maywood, IL (United States)

    1994-01-01

    Previous work has shown that HeLa cells stably transfected with an HIV-LTR-CAT construct are induced to express chloramphenicol acetyl transferase (CAT) following exposure to DNA-damaging agents such as ultraviolet radiation, {gamma} rays, neutrons, and others. In this report, the authors demonstrate that this induction of HIV-LTR transcription occurs when stably transfected HeLa cells are exposed to agents which mediate cell killing, such as UV radiation, electroporation of sucrose buffer, prolonged heating, and low and high pH. Cells cultured following UV exposure demonstrated a peak in CAT expression that is evidence in viable (but not necessarily cell division-competent) cells 24 h after exposure; this inductive response continued until at least 72 h after exposure. HIV-LTR induction was dose-dependent, and the amount of CAT transcription induced was correlated with the amount of cell killing that occurred in the culture. Other agents which caused no cell killing (such as heat-shock for up to 2 h, treatment with metronidazole, exposure to sunlight, vitamin C treatment, and others) had no effect on HIV-LTR induction. These results suggest that HIV transcription is induced as a consequence of the turn on of a cellular death or apoptotic pathway.

  19. Origins of Halophilic Microorganisms in Ancient Salt Deposits

    NSDL National Science Digital Library

    Terry McGenity

    This eight-page review article considers the evidence for and against long-term survival of halophilic microorganisms in ancient salt deposits. Included sections are hypersaline environments and their inhabitants, haloarchaea and halite precipitation, isolations of microorganisms from brines in salt mines, isolations of microorganisms from ancient rock salt, isolations of microorganisms directly from fluid inclusions, relationship of subsurface haloarchaea to surface isolates, dispersal of haloarchaea, and long-term survival of haloarchaea inside salt crystals.

  20. Impacts of invading alien plant species on water flows at stand and catchment scales

    PubMed Central

    Le Maitre, D. C.; Gush, M. B.; Dzikiti, S.

    2015-01-01

    There have been many studies of the diverse impacts of invasions by alien plants but few have assessed impacts on water resources. We reviewed the information on the impacts of invasions on surface runoff and groundwater resources at stand to catchment scales and covering a full annual cycle. Most of the research is South African so the emphasis is on South Africa's major invaders with data from commercial forest plantations where relevant. Catchment studies worldwide have shown that changes in vegetation structure and the physiology of the dominant plant species result in changes in surface runoff and groundwater discharge, whether they involve native or alien plant species. Where there is little change in vegetation structure [e.g. leaf area (index), height, rooting depth and seasonality] the effects of invasions generally are small or undetectable. In South Africa, the most important woody invaders typically are taller and deeper rooted than the native species. The impacts of changes in evaporation (and thus runoff) in dryland settings are constrained by water availability to the plants and, thus, by rainfall. Where the dryland invaders are evergreen and the native vegetation (grass) is seasonal, the increases can reach 300–400 mm/year. Where the native vegetation is evergreen (shrublands) the increases are ?200–300 mm/year. Where water availability is greater (riparian settings or shallow water tables), invading tree water-use can reach 1.5–2.0 times that of the same species in a dryland setting. So, riparian invasions have a much greater impact per unit area invaded than dryland invasions. The available data are scattered and incomplete, and there are many gaps and issues that must be addressed before a thorough understanding of the impacts at the site scale can be gained and used in extrapolating to watershed scales, and in converting changes in flows to water supply system yields. PMID:25935861

  1. Impacts of invading alien plant species on water flows at stand and catchment scales.

    PubMed

    Le Maitre, D C; Gush, M B; Dzikiti, S

    2015-01-01

    There have been many studies of the diverse impacts of invasions by alien plants but few have assessed impacts on water resources. We reviewed the information on the impacts of invasions on surface runoff and groundwater resources at stand to catchment scales and covering a full annual cycle. Most of the research is South African so the emphasis is on South Africa's major invaders with data from commercial forest plantations where relevant. Catchment studies worldwide have shown that changes in vegetation structure and the physiology of the dominant plant species result in changes in surface runoff and groundwater discharge, whether they involve native or alien plant species. Where there is little change in vegetation structure [e.g. leaf area (index), height, rooting depth and seasonality] the effects of invasions generally are small or undetectable. In South Africa, the most important woody invaders typically are taller and deeper rooted than the native species. The impacts of changes in evaporation (and thus runoff) in dryland settings are constrained by water availability to the plants and, thus, by rainfall. Where the dryland invaders are evergreen and the native vegetation (grass) is seasonal, the increases can reach 300-400 mm/year. Where the native vegetation is evergreen (shrublands) the increases are ?200-300 mm/year. Where water availability is greater (riparian settings or shallow water tables), invading tree water-use can reach 1.5-2.0 times that of the same species in a dryland setting. So, riparian invasions have a much greater impact per unit area invaded than dryland invasions. The available data are scattered and incomplete, and there are many gaps and issues that must be addressed before a thorough understanding of the impacts at the site scale can be gained and used in extrapolating to watershed scales, and in converting changes in flows to water supply system yields. PMID:25935861

  2. How could haloalkaliphilic microorganisms contribute to biotechnology?

    PubMed

    Zhao, Baisuo; Yan, Yanchun; Chen, Shulin

    2014-11-01

    Haloalkaliphiles are microorganisms requiring Na(+) concentrations of at least 0.5 mol·L(-1) and an alkaline pH of 9 for optimal growth. Their unique features enable them to make significant contributions to a wide array of biotechnological applications. Organic compatible solutes produced by haloalkaliphiles, such as ectoine and glycine betaine, are correlated with osmoadaptation and may serve as stabilizers of intracellular proteins, salt antagonists, osmoprotectants, and dermatological moisturizers. Haloalkaliphiles are an important source of secondary metabolites like rhodopsin, polyhydroxyalkanoates, and exopolysaccharides that play essential roles in biogeocycling organic compounds. These microorganisms also can secrete unique exoenzymes, including proteases, amylases, and cellulases, that are highly active and stable in extreme haloalkaline conditions and can be used for the production of laundry detergent. Furthermore, the unique metabolic pathways of haloalkaliphiles can be applied in the biodegradation and (or) biotransformation of a broad range of toxic industrial pollutants and heavy metals, in wastewater treatment, and in the biofuel industry. PMID:25372346

  3. Characterization of Microorganisms by MALDI Mass Spectrometry

    SciTech Connect

    Petersen, Catherine E.; Valentine, Nancy B.; Wahl, Karen L.

    2008-10-02

    Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for characterization and analysis of microorganisms, specifically bacteria, is described here as a rapid screening tool. The objective of this technique is not comprehensive protein analysis of a microorganism but rather a rapid screening of the organism and the accessible protein pattern for characterization and distinction. This method is based on the ionization of the readily accessible and easily ionizable portion of the protein profile of an organism that is often characteristic of different bacterial species. The utility of this screening approach is yet to reach its full potential but could be applied to food safety, disease outbreak monitoring in hospitals, culture stock integrity and verification, microbial forensics or homeland security applications.

  4. BioEd Online: Lessons: Microorganisms

    NSDL National Science Digital Library

    2012-03-02

    The BioEd Online site, created by the dedicated staff at the Baylor College of Medicine, is a veritable cornucopia of material for science educators. The lesson plans are all classroom tested and high-quality. This particular corner of the site focuses on the world of microorganisms. The site includes lessons, complete with video clips, slideshows, and .pdf files. The offerings here include "Comparing Sizes of Microorganisms," "Observing Different Microbes," and "Microbes and Disease." The videos are quite nice as they offer a brief introduction to each subject, along with suggestions for how to conduct the associated classroom activity. If visitors enjoy these lesson plans, they should explore the other categories under Classroom Lessons, such as Animals, Genetics, and History & Nature of Science.

  5. Microorganisms detection on substrates using QCL spectroscopy

    NASA Astrophysics Data System (ADS)

    Padilla-Jiménez, Amira C.; Ortiz-Rivera, William; Castro-Suarez, John R.; Ríos-Velázquez, Carlos; Vázquez-Ayala, Iris; Hernández-Rivera, Samuel P.

    2013-05-01

    Recent investigations have focused on the improvement of rapid and accurate methods to develop spectroscopic markers of compounds constituting microorganisms that are considered biological threats. Quantum cascade lasers (QCL) systems have revolutionized many areas of research and development in defense and security applications, including his area of research. Infrared spectroscopy detection based on QCL was employed to acquire mid infrared (MIR) spectral signatures of Bacillus thuringiensis (Bt), Escherichia coli (Ec) and Staphylococcus epidermidis (Se), which were used as biological agent simulants of biothreats. The experiments were carried out in reflection mode on various substrates such as cardboard, glass, travel baggage, wood and stainless steel. Chemometrics statistical routines such as principal component analysis (PCA) regression and partial least squares-discriminant analysis (PLS-DA) were applied to the recorded MIR spectra. The results show that the infrared vibrational techniques investigated are useful for classification/detection of the target microorganisms on the types of substrates studied.

  6. Bioleaching of chalcopyrite by moderately thermophilic microorganisms.

    PubMed

    Qin, Wenqing; Yang, Congren; Lai, Shaoshi; Wang, Jun; Liu, Kai; Zhang, Bo

    2013-02-01

    The leaching of chalcopyrite by moderately thermophilic microorganisms was investigated by employing cyclic voltammetry (CV), accompanying with the leaching behavior elucidation. Leaching experiment showed that there was clear benefit in leaching chalcopyrite within the low solution potential (below 400 mV vs. SCE), compared to the high potential leach (above 550 mV vs. SCE). Simultaneous maintenance of an appropriate concentration of total dissolved iron was necessary and also beneficial to leach chalcopyrite. The leaching results showed the existence of an optimum pH in the leaching of chalcopyrite by the moderately thermophilic microorganisms. The analysis of CV results revealed that the chalcopyrite was reduced to a series of intermediate products (such as talnakhite, bornite and chalcocite) in the cathodic, and then the intermediate product (chalcocite) was oxidized in the anodic. PMID:23246761

  7. Distribution of Aldoxime Dehydratase in Microorganisms

    PubMed Central

    Kato, Yasuo; Ooi, Ryoko; Asano, Yasuhisa

    2000-01-01

    The distribution of phenylacetaldoxime-degrading and pyridine-3-aldoxime-degrading ability was examined with intact cells of 975 microorganisms, including 45 genera of bacteria, 11 genera of actinomyces, 22 genera of yeasts, and 37 genera of fungi, by monitoring the decrease of the aldoximes by high-pressure liquid chromatography. The abilities were found to be widely distributed in bacteria, actinomyces, fungi, and some yeasts: 98 and 107 strains degraded phenylacetaldoxime and pyridine-3-aldoxime, respectively. All of the active strains exhibited not only the aldoxime-dehydration activity to form nitrile but also nitrile-hydrolyzing activity. On the other hand, all of 19 nitrile-degrading microorganisms (13 species, 7 genera) were found to exhibit aldoxime dehydration activity. It is shown that aldoxime dehydratase and nitrile-hydrolyzing activities are widely distributed among 188 aldoxime and 19 nitrile degraders and that the enzymes were induced by aldoximes or nitriles. PMID:10831401

  8. BioEd Online: Lessons: Microorganisms

    NSDL National Science Digital Library

    2012-03-05

    The BioEd Online site, created by the dedicated staff at the Baylor College of Medicine, is a veritable cornucopia of material for science educators. The lesson plans are all classroom tested and high-quality. This particular corner of the site focuses on the world of microorganisms. The site includes 15 lessons, complete with video clips, slideshows, and .pdf files. The offerings here include "Comparing Sizes of Microorganisms," "Observing Different Microbes," and "Microbes and Disease." The videos are quite nice as they offer a brief introduction to each subject, along with suggestions for how to conduct the associated classroom activity. If visitors enjoy these lesson plans, they should explore the other categories under Classroom Lessons, such as Animals, Genetics, and History & Nature of Science.

  9. The conformal Killing equation on forms -- prolongations and applications

    E-print Network

    A. Rod Gover; Josef Silhan

    2006-01-31

    We construct a conformally invariant vector bundle connection such that its equation of parallel transport is a first order system that gives a prolongation of the conformal Killing equation on differential forms. Parallel sections of this connection are related bijectively to solutions of the conformal Killing equation. We construct other conformally invariant connections, also giving prolongations of the conformal Killing equation, that bijectively relate solutions of the conformal Killing equation on $k$-forms to a twisting of the conformal Killing equation on (k - l)-forms for various integers l. These tools are used to develop a helicity raising and lowering construction in the general setting and on conformally Einstein manifolds.

  10. Neutrophils Exert Protection in the Early Tuberculous Granuloma by Oxidative Killing of Mycobacteria Phagocytosed from Infected Macrophages

    PubMed Central

    Yang, Chao-Tsung; Cambier, C.J.; Davis, J. Muse; Hall, Christopher J.; Crosier, Philip S.; Ramakrishnan, Lalita

    2013-01-01

    SUMMARY Neutrophils are typically the first responders in host defense against invading pathogens, which they destroy by both oxidative and nonoxidative mechanisms. However, despite a longstanding recognition of neutrophil presence at disease sites in tuberculosis, their role in defense against mycobacteria is unclear. Here we exploit the genetic tractability and optical transparency of zebrafish to monitor neutrophil behavior and its consequences during infection with Mycobacterium marinum, a natural fish pathogen. In contrast to macrophages, neutrophils do not interact with mycobacteria at initial infection sites. Neutrophils are subsequently recruited to the nascent granuloma in response to signals from dying infected macrophages within the granuloma, which they phagocytose. Some neutrophils then rapidly kill the internalized mycobacteria through NADPH oxidase-dependent mechanisms. Our results provide a mechanistic link to the observed patterns of neutrophils in human tuberculous granulomas and the susceptibility of humans with chronic granulomatous disease to mycobacterial infection. PMID:22980327

  11. Microorganic compounds in the Humber rivers

    Microsoft Academic Search

    W. A. House; D. Leach; J. L. A. Long; P. Cranwell; C. Smith; L. Bharwaj; A. Meharg; G. Ryland; D. O. Orr; J. Wright

    1997-01-01

    The concentrations of a range of micro-organic compounds in the Humber rivers have been measured at weekly intervals over a period of 1 year. The compounds include the triazine herbicides (simazine, atrazine, propazine, desmetryn and prometryn), selected organophosphorus insecticides (fenitrothion, malathion and parathion), phenylurea (chlorotoluron, diuron, isoproturon and linuron) and phenoxyacid herbicides (2,4-D, MCPA, MCPB and mecoprop), phenol derivatives (phenol,

  12. Autonomous support for microorganism research in space

    Microsoft Academic Search

    M. L. Fleet; J. D. Smith; D. M. Klaus; M. W. Luttges

    1993-01-01

    A preliminary design for performing on orbit, autonomous research on microorganisms and cultured cells\\/tissues is presented. The payload is designed to be compatible with the COMercial Experiment Transporter (COMET), an orbiter middeck locker interface and with Space Station Freedom. Uplink\\/downlink capabilities and sample return through controlled reentry are available for all carriers. Autonomous testing activities are preprogrammed with in-flight reprogrammability.

  13. Impact of microorganism on polonium volatilization

    Microsoft Academic Search

    N. Momoshima; A. Fukuda; A. Ishida; C. Yoshinaga

    2007-01-01

    Volatilization of polonium by microorganisms, Chromobacterium violaceum, Escherichia coli and Bacillus subtilis was examined for pure cultures in LB medium at 30 °C, showing relative Po emission intensity 100, 10 and 1, respectively.\\u000a Chromobacterium violaceum pre-cultured in LB medium without Po and suspended in water with Po showed high Po volatilization in spite of poor nutriment\\u000a condition. Antibiotics inhibit volatilization

  14. Thermophilic chitinolytic microorganisms of brown semidesert soil

    Microsoft Academic Search

    N. A. Manucharova; A. N. Vlasenko; T. P. Tourova; A. N. Panteleeva; A. L. Stepanov; G. M. Zenova

    2008-01-01

    In brown semidesert soil, thermophilic prokaryotic organisms identified as Streptomyces roseolilacinus and Silanimonas lenta were shown to play the main role in chitin transformation at 50°C. The phylogenetic positions of the isolated dominant chitinolytic\\u000a microorganisms were determined on the basis of 16S rRNA gene sequencing. The consumption of chitin as a source of carbon and\\u000a nitrogen by both the bacterium

  15. Control of microorganisms in flowing nutrient solutions

    NASA Astrophysics Data System (ADS)

    Evans, R. D.

    1994-11-01

    Controlling microorganisms in flowing nutrient solutions involves different techniques when targeting the nutrient solution, hardware surfaces in contact with the solution, or the active root zone. This review presents basic principles and applications of a number of treatment techniques, including disinfection by chemicals, ultrafiltration, ultrasonics, and heat treatment, with emphasis on UV irradiation and ozone treatment. Procedures for control of specific pathogens by nutrient solution conditioning also are reviewed.

  16. Protein Languages Differ Depending on Microorganism Lifestyle

    PubMed Central

    Grzymski, Joseph J.; Marsh, Adam G.

    2014-01-01

    Few quantitative measures of genome architecture or organization exist to support assumptions of differences between microorganisms that are broadly defined as being free-living or pathogenic. General principles about complete proteomes exist for codon usage, amino acid biases and essential or core genes. Genome-wide shifts in amino acid usage between free-living and pathogenic microorganisms result in fundamental differences in the complexity of their respective proteomes that are size and gene content independent. These differences are evident across broad phylogenetic groups–a result of environmental factors and population genetic forces rather than phylogenetic distance. A novel comparative analysis of amino acid usage–utilizing linguistic analyses of word frequency in language and text–identified a global pattern of higher peptide word repetition in 376 free-living versus 421 pathogen genomes across broad ranges of genome size, G+C content and phylogenetic ancestry. This imprint of repetitive word usage indicates free-living microorganisms have a bias for repetitive sequence usage compared to pathogens. These findings quantify fundamental differences in microbial genomes relative to life-history function. PMID:24828817

  17. Biomining: metal recovery from ores with microorganisms.

    PubMed

    Schippers, Axel; Hedrich, Sabrina; Vasters, Jürgen; Drobe, Malte; Sand, Wolfgang; Willscher, Sabine

    2014-01-01

    Biomining is an increasingly applied biotechnological procedure for processing of ores in the mining industry (biohydrometallurgy). Nowadays the production of copper from low-grade ores is the most important industrial application and a significant part of world copper production already originates from heap or dump/stockpile bioleaching. Conceptual differences exist between the industrial processes of bioleaching and biooxidation. Bioleaching is a conversion of an insoluble valuable metal into a soluble form by means of microorganisms. In biooxidation, on the other hand, gold is predominantly unlocked from refractory ores in large-scale stirred-tank biooxidation arrangements for further processing steps. In addition to copper and gold production, biomining is also used to produce cobalt, nickel, zinc, and uranium. Up to now, biomining has merely been used as a procedure in the processing of sulfide ores and uranium ore, but laboratory and pilot procedures already exist for the processing of silicate and oxide ores (e.g., laterites), for leaching of processing residues or mine waste dumps (mine tailings), as well as for the extraction of metals from industrial residues and waste (recycling). This chapter estimates the world production of copper, gold, and other metals by means of biomining and chemical leaching (bio-/hydrometallurgy) compared with metal production by pyrometallurgical procedures, and describes new developments in biomining. In addition, an overview is given about metal sulfide oxidizing microorganisms, fundamentals of biomining including bioleaching mechanisms and interface processes, as well as anaerobic bioleaching and bioleaching with heterotrophic microorganisms. PMID:23793914

  18. Effect of Gas Hydrate Formers on Microorganisms

    PubMed Central

    Prior, B. A.; Fennema, O.; Marth, E. H.

    1970-01-01

    Various bacteria, yeasts, and molds important to the food industry were incubated in aerosol cans containing A C Broth and one of the following three gas hydrate formers: propane, dichlorodifluoromethane (f-12), and 1,1-difluoro-1-chloroethane (f-142b). Most hydrate formers were tested at three concentrations: low (vapor state), intermediate (liquid state, low level), and high (liquid state, high level). Samples were continuously agitated for 48 hr at 21 ± 3 C. Changes in numbers of microorganisms were determined by plate count. With hydrate formers in the vapor state, propane was more toxic to the microorganisms tested than either f-12 or f-142b. The most resistant organisms from these trials were then tested against f-12 or f-142b in the liquid state. Hydrate formers were far more toxic in the liquid state than in the vapor state. With the exception of sporulated cultures of Bacillus cereus, all microorganisms tested were greatly reduced in numbers when agitated for 48 hr at 21 C in the presence of f-12 or f-142b. PMID:5456934

  19. Dynamic kill: controlling wild wells a new way

    SciTech Connect

    Blount, E.M.; Soeiinah, E.

    1981-10-01

    Dynamic kill describes a technique for terminating a blowout utilizing flowing frictional pressure to supplement the hydrostatic pressure of the kill fluid being injected through the relief well and up the blowing well. Therefore, a lighter kill fluid such as water can be implemented. The objective is to allow a blowout to be killed without breaking down the formation so the maximum amount of fluid can be circulated through the relief well by not losing fluid to a fractured formation. This allows optimum control during the kill operation and stable communication between the two wells. By allowing more fluid to be applied to the kill through one relief well, dynamic kill also increases the probability that one relief well will be sufficient. When the well is dynamically dead, the initial kill fluid, which will usually be too light to hold the well dead in a static condition, is replaced with a heavier kill mud. In fact, three weights of mud may be required to allow control during the transition from low density initial dynamic kill mud to heavy final kill mud. 5 refs.

  20. The Proteasome-Ubiquitin System Is Required for Efficient Killing of Intracellular Streptococcus pneumoniae by Brain Endothelial Cells

    PubMed Central

    Iovino, Federico; Gradstedt, Henrik

    2014-01-01

    ABSTRACT Streptococcus pneumoniae (pneumococcus) is a Gram-positive bacterium that causes serious invasive diseases, such as pneumonia, bacteremia, and meningitis, with high morbidity and mortality throughout the world. Before causing invasive disease, S. pneumoniae encounters cellular barriers, which are often composed of endothelial cells, like the alveolar-capillary barrier and the blood-brain barrier. S. pneumoniae adheres to endothelial cells and may invade them, which requires an efficient host response to the intracellular bacteria. The precise intracellular fate of S. pneumoniae during infection still remains a subject of debate. The proteasome-ubiquitin system is largely responsible for the degradation of misfolded, damaged, or no-longer-useful proteins. Recently, the role of the proteasome-ubiquitin system in the clearing of invading bacteria and viruses has been more closely studied. In this study, we show that inhibition of the proteasome-ubiquitin system leads to a marked increase in S. pneumoniae survival inside host cells. Immunofluorescence analysis showed that intracellular pneumococci colocalized with proteasome and ubiquitin in human endothelial cells in vitro. Confocal imaging analysis demonstrated that in the brains of mice intravenously infected with S. pneumoniae, the bacteria were inside endothelial cells, where they colocalized with proteasome and ubiquitin signals. In conclusion, our data indicate that a fully functional proteasome-ubiquitin system in endothelial cells is crucial for efficient killing of intracellular S. pneumoniae. PMID:24987087

  1. The adaptive value of remnant native plants in invaded communities: an example from the Great Basin.

    PubMed

    Leger, Elizabeth A

    2008-07-01

    Changes in the species composition of biotic communities may alter patterns of natural selection occurring within them. Native perennial grass species in the Intermountain West are experiencing a shift in the composition of interspecific competitors from primarily perennial species to an exotic, annual grass. Thus traits that confer an advantage to perennial grasses in the presence of novel annual competitors may evolve in invaded communities. Here I show that such traits are apparent in populations of a native perennial grass, big squirreltail (Elymus multisetus M.E. Jones), exposed to cheatgrass (Bromus tectorum L.) competitors. Dormant big squirreltail plants were collected from cheatgrass-invaded and uninvaded sites near Bordertown, California, USA, a mid-elevation (1600 m) sagebrush community, and transplanted into pots in a greenhouse. Individual plants were split into equal halves. One half was grown with competition from cheatgrass, and the other half was grown without competition. Plants collected from invaded sites responded more quickly to watering, growing more leaves in the first 10 days after transplanting. In addition, big squirreltail plants collected from invaded areas experienced a smaller decrease in plant size when grown with competition than did plants collected from uninvaded areas. Accordingly, while there were fewer big squirreltail individuals in the invaded sites, they were more competitive with cheatgrass than were the more abundant conspecifics in nearby uninvaded areas. It is possible that annual grasses were the selective force that caused these population differences, which may contribute to the long-term persistence of the native populations. While it is tempting to restore degraded areas to higher densities of natives (usually done by bringing in outside seed material), such actions may impede long-term adaptation to new conditions by arresting or reversing the direction of ongoing natural selection in the resident population. If hot spots of rapid evolutionary change can be identified within invaded systems, these areas should be managed to promote desirable change and could serve as possible sources of restoration material or reveal traits that should be prioritized during the development of restoration seed material. PMID:18686583

  2. Micro-sociology of mass rampage killings.

    PubMed

    Collins, Randall

    2014-01-01

    Spectacular but very rare violent events such as mass killings by habitual non-criminals cannot be explained by factors which are very widespread, such as possession of firearms, being a victim of bullying, an introvert, or a career failure. A stronger clue is clandestine preparation of attack by one or two individuals, against randomly chosen representatives of a hated collective identity. Mass killers develop a deep back-stage, obsessed with planning their attack, overcoming social inferiority and isolation by an emotion of clandestine excitement. PMID:25179819

  3. Bacterial Killing by Dry Metallic Copper Surfaces?

    PubMed Central

    Santo, Christophe Espírito; Lam, Ee Wen; Elowsky, Christian G.; Quaranta, Davide; Domaille, Dylan W.; Chang, Christopher J.; Grass, Gregor

    2011-01-01

    Metallic copper surfaces rapidly and efficiently kill bacteria. Cells exposed to copper surfaces accumulated large amounts of copper ions, and this copper uptake was faster from dry copper than from moist copper. Cells suffered extensive membrane damage within minutes of exposure to dry copper. Further, cells removed from copper showed loss of cell integrity. Acute contact with metallic copper surfaces did not result in increased mutation rates or DNA lesions. These findings are important first steps for revealing the molecular sensitive targets in cells lethally challenged by exposure to copper surfaces and provide a scientific explanation for the use of copper surfaces as antimicrobial agents for supporting public hygiene. PMID:21148701

  4. "Brain Invaders": a prototype of an open-source P300-based video game working with the OpenViBE platform.

    E-print Network

    Paris-Sud XI, Université de

    1 "Brain Invaders": a prototype of an open-source P300- based video game working with the Open. FRANCE Marco.Congedo@gmail.com We have developed the prototype of a pure-BCI video game based on the well known vintage video game "Space Invaders". In our "Brain Invaders" a number of aliens are displayed

  5. Mycobacterium avium Invades the Intestinal Mucosa Primarily by Interacting with Enterocytes

    PubMed Central

    Sangari, Felix J.; Goodman, Joseph; Petrofsky, Mary; Kolonoski, Peter; Bermudez, Luiz E.

    2001-01-01

    Previous studies have demonstrated that Mycobacterium avium can invade intestinal epithelial cells both in vitro and in vivo. When given to mice orally, M. avium preferentially interacts with the intestinal mucosa at the terminal ileum. We evaluated the mechanism(s) of M. avium binding and invasion of the intestinal mucosa using three different systems: (i) electron microscopy following administration of M. avium into an intestinal loop in mice, (ii) quantitative comparison of the bacterial load in Peyer's patch areas of the terminal ileum versus areas that do not contain Peyer's patches, and (iii) investigation of the ability of M. avium to cause disseminated infection following oral administration using B-cell-deficient mice, lacking Peyer's patches, in comparison with C57BL/6 black mice. By all approaches, M. avium was found to invade the intestinal mucosa by interacting primarily with enterocytes and not with M cells. PMID:11179321

  6. Mycobacterium avium invades the intestinal mucosa primarily by interacting with enterocytes.

    PubMed

    Sangari, F J; Goodman, J; Petrofsky, M; Kolonoski, P; Bermudez, L E

    2001-03-01

    Previous studies have demonstrated that Mycobacterium avium can invade intestinal epithelial cells both in vitro and in vivo. When given to mice orally, M. avium preferentially interacts with the intestinal mucosa at the terminal ileum. We evaluated the mechanism(s) of M. avium binding and invasion of the intestinal mucosa using three different systems: (i) electron microscopy following administration of M. avium into an intestinal loop in mice, (ii) quantitative comparison of the bacterial load in Peyer's patch areas of the terminal ileum versus areas that do not contain Peyer's patches, and (iii) investigation of the ability of M. avium to cause disseminated infection following oral administration using B-cell-deficient mice, lacking Peyer's patches, in comparison with C57BL/6 black mice. By all approaches, M. avium was found to invade the intestinal mucosa by interacting primarily with enterocytes and not with M cells. PMID:11179321

  7. Screening of biosurfactants from cloud microorganisms

    NASA Astrophysics Data System (ADS)

    Sancelme, Martine; Canet, Isabelle; Traikia, Mounir; Uhliarikova, Yveta; Capek, Peter; Matulova, Maria; Delort, Anne-Marie; Amato, Pierre

    2015-04-01

    The formation of cloud droplets from aerosol particles in the atmosphere is still not well understood and a main source of uncertainties in the climate budget today. One of the principal parameters in these processes is the surface tension of atmospheric particles, which can be strongly affected by trace compounds called surfactants. Within a project devoted to bring information on atmospheric surfactants and their effects on cloud droplet formation, we focused on surfactants produced by microorganisms present in atmospheric waters. From our unique collection of microorganisms, isolated from cloud water collected at the Puy-de-Dôme (France),1 we undertook a screening of this bank for biosurfactant producers. After extraction of the supernatants of the pure cultures, surface tension of crude extracts was determined by the hanging drop technique. Results showed that a wide variety of microorganisms are able to produce biosurfactants, some of them exhibiting strong surfactant properties as the resulting tension surface decreases to values less then 35 mN.m-1. Preliminary analytical characterization of biosurfactants, obtained after isolation from overproducing cultures of Rhodococcus sp. and Pseudomonas sp., allowed us to identify them as belonging to two main classes, namely glycolipids and glycopeptides. 1. Vaïtilingom, M.; Attard, E.; Gaiani, N.; Sancelme, M.; Deguillaume, L.; Flossmann, A. I.; Amato, P.; Delort, A. M. Long-term features of cloud microbiology at the puy de Dôme (France). Atmos. Environ. 2012, 56, 88-100. Acknowledgements: This work is supported by the French-USA ANR SONATA program and the French-Slovakia programs Stefanik and CNRS exchange.

  8. Resistance of soil microorganisms to starvation.

    NASA Technical Reports Server (NTRS)

    Chen, M.; Alexander, M.

    1972-01-01

    Most groups of soil microorganisms died when exposed to prolonged starvation in a carbon-free solution, but the relative abundance of Bacillus and actinomycetes increased with time. Certain nonspore-forming bacteria also persisted. The ability of individual soil isolates to endure starvation in solution was not correlated with their glycogen content or rate of endogenous respiration. However, cells of the resistant populations were rich in poly-beta-hydroxybutyrate, whereas the starvation-susceptible bacteria generally contained little of this substance. Poly-beta-hydroxybutyrate was used rapidly in cells deprived of exogenous sources of carbon.

  9. Co-invaders: The effects of alien parasites on native hosts

    PubMed Central

    Lymbery, Alan J.; Morine, Mikayla; Kanani, Hosna Gholipour; Beatty, Stephen J.; Morgan, David L.

    2014-01-01

    We define co-introduced parasites as those which have been transported with an alien host to a new locality, outside of their natural range, and co-invading parasites as those which have been co-introduced and then spread to new, native hosts. Of 98 published studies of co-introductions, over 50% of hosts were freshwater fishes and 49% of parasites were helminths. Although we would expect parasites with simple, direct life cycles to be much more likely to be introduced and establish in a new locality, a substantial proportion (36%) of co-introductions were of parasites with an indirect life cycle. Seventy-eight per cent of co-introduced parasites were found in native host species and can therefore be classed as co-invaders. Host switching was equally common among parasites with direct and indirect life cycles. The magnitude of the threat posed to native species by co-invaders will depend, among other things, on parasite virulence. In 16 cases where co-introduced parasites have switched to native hosts and information was available on relative virulence, 14 (85%) were more virulent in native hosts than in the co-introduced alien host. We argue that this does not necessarily support the naïve host theory that co-invading parasites will have greater pathogenic effects in native hosts with which they have no coevolutionary history, but may instead be a consequence of the greater likelihood for parasites with lower virulence in their natural host to be co-introduced. PMID:25180161

  10. Chinese mitten crab Eriocheir sinensis in the Baltic Sea—a supply-side invader?

    Microsoft Academic Search

    Henn Ojaveer; Stephan Gollasch; Andres Jaanus; Jonne Kotta; Ari O. Laine; Atis Minde; Monika Normant; Vadim E. Panov

    2007-01-01

    Although the Chinese mitten crab Eriocheir sinensis (H. Milne-Edwards, 1853) (Crustacea, Decapoda, Varunidae) invaded the Baltic Sea about 80 years ago, published information\\u000a on its present distribution and abundance in this region is lacking. We provide here information on its Baltic-wide distribution\\u000a and long-term population dynamics. The species has been found all over the coastal Baltic Sea and also in some

  11. More than One Way to Invade: Lessons from Genetic Studies of Carcinus Shore Crabs

    Microsoft Academic Search

    John A. Darling

    \\u000a The European green crab Carcinus maenas is one of the world’s most widely recognized marine invaders. The success of this species has provided opportunities to explore\\u000a genetic patterns associated with establishment and population expansion following independent introduction events to widely\\u000a different recipient ecosystems. Recent studies have revealed an extraordinary diversity of such patterns. Globally, genetic\\u000a reconstruction of invasion histories suggests

  12. Life-history Habitat Matching in Invading Non-native Plant Species

    Microsoft Academic Search

    Thomas J. Stohlgren; Catherine Crosier; Geneva W. Chong; Debra Guenther; Paul Evangelista

    2005-01-01

    We briefly reviewed the literature on habitat matching in invading non-native plant species. Then we hypothesized that the\\u000a richness and cover of native annual and perennial plant species integrate complex local information of vegetation and soils\\u000a that would help to predict invasion success by similarly adapted non-native plant species. We tested these ‘life-history habitat\\u000a matching’ relationships in 603 0.1-ha plots,

  13. Factors associated with woody alien species distribution in a newly invaded mountain system of central Argentina

    Microsoft Academic Search

    Melisa A. GiorgisPaula; Paula A. Tecco; Ana M. Cingolani; Daniel Renison; Paula Marcora; Valeria Paiaro

    2011-01-01

    To help determine the major factors associated with alien plant in a newly invaded mountain range; we analyzed the distribution\\u000a patterns of woody alien species along the altitudinal gradient of the Córdoba mountains, in relation to biotic, abiotic and\\u000a anthropogenic factors. We selected 303 plots using a Geographic Information System (GIS) covering all the variability of these\\u000a factors. In the

  14. Hepatocellular Carcinoma Invading the Main Portal Vein: Treatment with Transcatheter Arterial Chemoembolization and Portal Vein Stenting

    Microsoft Academic Search

    Xue-Bin Zhang; Jian-Hua Wang; Zhi-Ping Yan; Sheng Qian; Rong Liu

    2009-01-01

    To retrospectively analyze the therapeutic results of percutaneous transhepatic portal vein stenting (PTPVS) and transcatheter\\u000a arterial chemoembolization (TACE) treatment in 58 patients with hepatocellular carcinoma (HCC) invading the main portal vein\\u000a (MPV). A total of 58 procedures of PTPVS were performed, immediately after which TACE was undertaken to control HCC. The clinical\\u000a effects, complications, digital subtraction angiographic appearance, stent patency

  15. Predicting plant invaders in the Mediterranean through a weed risk assessment system

    Microsoft Academic Search

    Núria Gassó; Corina Basnou

    2010-01-01

    Risk assessment schemes have been developed to identify potential invasive species, prevent their spread and reduce their\\u000a damaging effects. One of the most promising tools for detecting plant invaders is the weed risk assessment (WRA) scheme developed\\u000a for Australia. Our study explores whether the Australian WRA can satisfactorily predict the invasion status of alien plants\\u000a in the Mediterranean Basin by

  16. Response of the invader Cortaderia selloana and two coexisting natives to competition and water stress

    Microsoft Academic Search

    Roser Domènech

    2008-01-01

    Alien species’ resistance and adjustment to water stress and plant competition might largely determine the success of invasions\\u000a in Mediterranean ecosystems because water availability is often limiting biomass production. Two outdoor pot experiments were\\u000a conducted to test the hypotheses that at the recruitment stage the invader perennial tussock grass Cortaderia selloana is a superior competitor, and that it is more

  17. Parasitism may enhance rather than reduce the predatory impact of an invader.

    PubMed

    Dick, Jaimie T A; Armstrong, Michael; Clarke, Hazel C; Farnsworth, Keith D; Hatcher, Melanie J; Ennis, Marilyn; Kelly, Andrew; Dunn, Alison M

    2010-10-23

    Invasive species can have profound impacts on communities and it is increasingly recognized that such effects may be mediated by parasitism. The 'enemy release' hypothesis posits that invaders may be successful and have high impacts owing to escape from parasitism. Alternatively, we hypothesize that parasites may increase host feeding rates and hence parasitized invaders may have increased community impacts. Here, we investigate the influence of parasitism on the predatory impact of the invasive freshwater amphipod Gammarus pulex. Up to 70 per cent of individuals are infected with the acanthocephalan parasite Echinorhynchus truttae, but parasitized individuals were no different in body condition to those unparasitized. Parasitized individuals consumed significantly more prey (Asellus aquaticus; Isopoda) than did unparasitized individuals. Both parasitized and unparasitized individuals displayed Type-II functional responses (FRs), with the FR for parasitized individuals rising more steeply, with a higher asymptote, compared with unparasitized individuals. While the parasite reduced the fitness of individual females, we predict a minor effect on population recruitment because of low parasite prevalence in the peak reproductive period. The parasite thus has a large per capita effect on predatory rate but a low population fitness effect, and thus may enhance rather than reduce the impact of this invader. PMID:20392715

  18. Cas6 is an endoribonuclease that generates guide RNAs for invader defense in prokaryotes

    SciTech Connect

    Carte, Jason; Wang, Ruiying; Li, Hong; Terns, Rebecca M.; Terns, Michael P. (FSU); (Georgia)

    2010-11-09

    An RNA-based gene silencing pathway that protects bacteria and archaea from viruses and other genome invaders is hypothesized to arise from guide RNAs encoded by CRISPR loci and proteins encoded by the cas genes. CRISPR loci contain multiple short invader-derived sequences separated by short repeats. The presence of virus-specific sequences within CRISPR loci of prokaryotic genomes confers resistance against corresponding viruses. The CRISPR loci are transcribed as long RNAs that must be processed to smaller guide RNAs. Here we identified Pyrococcus furiosus Cas6 as a novel endoribonuclease that cleaves CRISPR RNAs within the repeat sequences to release individual invader targeting RNAs. Cas6 interacts with a specific sequence motif in the 5{prime} region of the CRISPR repeat element and cleaves at a defined site within the 3{prime} region of the repeat. The 1.8 angstrom crystal structure of the enzyme reveals two ferredoxin-like folds that are also found in other RNA-binding proteins. The predicted active site of the enzyme is similar to that of tRNA splicing endonucleases, and concordantly, Cas6 activity is metal-independent. cas6 is one of the most widely distributed CRISPR-associated genes. Our findings indicate that Cas6 functions in the generation of CRISPR-derived guide RNAs in numerous bacteria and archaea.

  19. Parasitism may enhance rather than reduce the predatory impact of an invader

    PubMed Central

    Dick, Jaimie T. A.; Armstrong, Michael; Clarke, Hazel C.; Farnsworth, Keith D.; Hatcher, Melanie J.; Ennis, Marilyn; Kelly, Andrew; Dunn, Alison M.

    2010-01-01

    Invasive species can have profound impacts on communities and it is increasingly recognized that such effects may be mediated by parasitism. The ‘enemy release’ hypothesis posits that invaders may be successful and have high impacts owing to escape from parasitism. Alternatively, we hypothesize that parasites may increase host feeding rates and hence parasitized invaders may have increased community impacts. Here, we investigate the influence of parasitism on the predatory impact of the invasive freshwater amphipod Gammarus pulex. Up to 70 per cent of individuals are infected with the acanthocephalan parasite Echinorhynchus truttae, but parasitized individuals were no different in body condition to those unparasitized. Parasitized individuals consumed significantly more prey (Asellus aquaticus; Isopoda) than did unparasitized individuals. Both parasitized and unparasitized individuals displayed Type-II functional responses (FRs), with the FR for parasitized individuals rising more steeply, with a higher asymptote, compared with unparasitized individuals. While the parasite reduced the fitness of individual females, we predict a minor effect on population recruitment because of low parasite prevalence in the peak reproductive period. The parasite thus has a large per capita effect on predatory rate but a low population fitness effect, and thus may enhance rather than reduce the impact of this invader. PMID:20392715

  20. Dispersion in time and space affect mating success and Allee effects in invading gypsy moth populations.

    PubMed

    Robinet, C; Lance, D R; Thorpe, K W; Onufrieva, K S; Tobin, P C; Liebhold, A M

    2008-09-01

    1. Understanding why invading populations sometimes fail to establish is of considerable relevance to the development of strategies for managing biological invasions. 2. Newly arriving populations tend to be sparse and are often influenced by Allee effects. Mating failure is a typical cause of Allee effects in low-density insect populations, and dispersion of individuals in space and time can exacerbate mate-location failure in invading populations. 3. Here we evaluate the relative importance of dispersal and sexual asynchrony as contributors to Allee effects in invading populations by adopting as a case study the gypsy moth (Lymantria dispar L.), an important insect defoliator for which considerable demographic information is available. 4. We used release-recapture experiments to parameterize a model that describes probabilities that males locate females along various spatial and temporal offsets between male and female adult emergence. 5. Based on these experimental results, we developed a generalized model of mating success that demonstrates the existence of an Allee threshold, below which introduced gypsy moth populations are likely to go extinct without any management intervention. PMID:18557957

  1. Killing of adherent oral microbes by a non-thermal atmospheric plasma jet.

    PubMed

    Rupf, Stefan; Lehmann, Antje; Hannig, Matthias; Schäfer, Barbara; Schubert, Andreas; Feldmann, Uwe; Schindler, Axel

    2010-02-01

    Atmospheric plasma jets are being intensively studied with respect to potential applications in medicine. The aim of this in vitro study was to test a microwave-powered non-thermal atmospheric plasma jet for its antimicrobial efficacy against adherent oral micro-organisms. Agar plates and dentin slices were inoculated with 6 log(10) c.f.u. cm(-2) of Lactobacillus casei, Streptococcus mutans and Candida albicans, with Escherichia coli as a control. Areas of 1 cm(2) on the agar plates or the complete dentin slices were irradiated with a helium plasma jet for 0.3, 0.6 or 0.9 s mm(-2), respectively. The agar plates were incubated at 37 degrees C, and dentin slices were vortexed in liquid media and suspensions were placed on agar plates. The killing efficacy of the plasma jet was assessed by counting the number of c.f.u. on the irradiated areas of the agar plates, as well as by determination of the number of c.f.u. recovered from dentin slices. A microbe-killing effect was found on the irradiated parts of the agar plates for L. casei, S. mutans, C. albicans and E. coli. The plasma-jet treatment reduced the c.f.u. by 3-4 log(10) intervals on the dentin slices in comparison to recovery rates from untreated controls. The microbe-killing effect was correlated with increasing irradiation times. Thus, non-thermal atmospheric plasma jets could be used for the disinfection of dental surfaces. PMID:19910483

  2. Aquatic Invaders

    NSDL National Science Digital Library

    In this lesson plan students will explore the ways that native species interact in a healthy Chesapeake Bay. They will then learn about some of the ways that exotic or invasive species can threaten the balance of the ecosystem. Students will discover how the various elements of the Bay ecosystem are interconnected and investigate some of the issues associated with invasive species.

  3. Killing sections and sigma models with Lie algebroid targets

    E-print Network

    Bruce, Andrew James

    2015-01-01

    We define and examine the notion of a Killing section of a Riemannian Lie algebroid as a natural generalisation of a Killing vector field. We show that the various expression for a vector field to be Killing naturally generalise to the setting of Lie algebroids. As an application we examine the internal symmetries of a class of sigma models for which the target space is a Riemannian Lie algebroid. Critical points of these sigma models are interpreted as generalised harmonic maps.

  4. Killing Symmetries in $\\mathcal{H}$-Spaces with $?$

    E-print Network

    Adam Chudecki; Maciej Przanowski

    2013-03-05

    All Killing symmetries in complex $\\mathcal{H}$-spaces with $\\Lambda$ in terms of the Pleba\\'nski - Robinson - Finley coordinate system are found. All $\\mathcal{H}$-metrics with $\\Lambda$ admitting a null Killing vector are explicitly given. It is shown that the problem of non-null Killing vector reduces to looking for solution of the Boyer - Finley - Pleba\\'nski (Toda field) equation

  5. Birkhoff theorem and conformal Killing-Yano tensors

    E-print Network

    Ferrando, Joan Josep

    2015-01-01

    We analyze the main geometric conditions imposed by the hypothesis of the Jebsen-Birkhoff theorem. We show that the result (existence of an additional Killing vector) does not necessarily require a three-dimensional isometry group on two-dimensional orbits but only the existence of a conformal Killing-Yano tensor. In this approach the (additional) isometry appears as the known invariant Killing vector that the ${\\cal D}$-metrics admit.

  6. Birkhoff theorem and conformal Killing-Yano tensors

    E-print Network

    Joan Josep Ferrando; Juan Antonio Sáez

    2015-05-13

    We analyze the main geometric conditions imposed by the hypothesis of the Jebsen-Birkhoff theorem. We show that the result (existence of an additional Killing vector) does not necessarily require a three-dimensional isometry group on two-dimensional orbits but only the existence of a conformal Killing-Yano tensor. In this approach the (additional) isometry appears as the known invariant Killing vector that the ${\\cal D}$-metrics admit.

  7. Killing sections and sigma models with Lie algebroid targets

    E-print Network

    Andrew James Bruce

    2015-06-25

    We define and examine the notion of a Killing section of a Riemannian Lie algebroid as a natural generalisation of a Killing vector field. We show that the various expression for a vector field to be Killing naturally generalise to the setting of Lie algebroids. As an application we examine the internal symmetries of a class of sigma models for which the target space is a Riemannian Lie algebroid. Critical points of these sigma models are interpreted as generalised harmonic maps.

  8. Birkhoff theorem and conformal Killing-Yano tensors

    NASA Astrophysics Data System (ADS)

    Ferrando, Joan Josep; Sáez, Juan Antonio

    2015-06-01

    We analyze the main geometric conditions imposed by the hypothesis of the Jebsen-Birkhoff theorem. We show that the result (existence of an additional Killing vector) does not necessarily require a three-dimensional isometry group on two-dimensional orbits but only the existence of a conformal Killing-Yano tensor. In this approach the (additional) isometry appears as the known invariant Killing vector that the -metrics admit.

  9. Roles of antibodies and complement in phagocytic killing of enterococci.

    PubMed Central

    Arduino, R C; Murray, B E; Rakita, R M

    1994-01-01

    The contributions of complement and antibodies to polymorphonuclear leukocyte (PMN)-mediated killing of enterococci were investigated with pooled normal human serum (PNHS) or immune human sera (IHS) from patients with serious enterococcal infections. Each IHS containing antienterococcal antibodies demonstrated by enzyme-linked immunosorbent assay and Western blotting (immunoblotting) was examined with the enterococcus strain isolated from the same patient. PNHS promoted PMN-mediated killing of enterococci similar to that for IHS. PMN-mediated killing was consistently abrogated after preopsonization with heat-inactivated PNHS, but some heat-inactivated IHS supported neutrophil bactericidal activity. Inhibition of the classical pathway of complement by chelation of either PNHS or IHS with Mg-EGTA [Mg-ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] did not alter PMN-mediated killing, suggesting that activation of the alternative pathway of complement is sufficient to promote killing of enterococci by PMNs. PMN-mediated killing assays were also performed with normal rabbit serum and immune rabbit serum against enterococci. Preopsonization with heat-inactivated immune rabbit serum resulted in PMN-mediated killing of enterococci, which was ablated after adsorption of the serum with the same isolate used for immunization. The influence of different phenotypic enterococcal traits on neutrophil-mediated killing was also investigated. Similar kinetics of killing were observed for derivatives of Enterococcus faecalis strains regardless of resistance to antimicrobial agents or production of beta-lactamase, hemolysin, gelatinase, or surface proteins involved in the aggregative response to pheromones. In summary, PMN-mediated killing of enterococci appears to depend primarily on complement activation by either the classical or the alternative pathway. Human antienterococcal antibodies generated during infection variably promoted neutrophil bactericidal activity, while antibody raised in a rabbit supported PMN-mediated killing of the organism examined. Finally, the different phenotypic properties of E. faecalis examined did not influence the neutrophil-mediated killing of these organisms. Images PMID:8112874

  10. Industrial and environmental applications of halophilic microorganisms.

    PubMed

    Oren, Aharon

    2010-01-01

    In comparison with the thermophilic and the alkaliphilic extremophiles, halophilic microorganisms have as yet found relatively few biotechnological applications. Halophiles are involved in centuries-old processes such as the manufacturing of solar salt from seawater and the production of traditional fermented foods. Two biotechnological processes involving halophiles are highly successful: the production of beta-carotene by the green alga Dunaliella and the production of ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid), used as a stabilizer for enzymes and now also applied in cosmetic products, from moderately halophilic bacteria. The potential use of bacteriorhodopsin, the retinal protein proton pump of Halobacterium, in optoelectronic devices and photochemical processes is being explored, and may well lead to commercial applications in the near future. Demand for salt-tolerant enzymes in current manufacturing or related processes is limited. Other possible uses of halophilic microorganisms such as treatment of saline and hypersaline wastewaters, and the production of exopolysaccharides, poly-beta-hydroxyalkanoate bioplastics and biofuel are being investigated, but no large-scale applications have yet been reported. PMID:20662374

  11. From chemosensing in microorganisms to practical biosensors

    NASA Astrophysics Data System (ADS)

    Ghosh, Surya K.; Kundu, Tapanendu; Sain, Anirban

    2012-11-01

    Microorganisms like bacteria can sense concentrations of chemoattractants in their medium very accurately. They achieve this through interaction between the receptors on their cell surfaces and chemoattractant molecules (like sugar). Physical processes like diffusion set some limits on the accuracy of detection, which was discussed by Berg and Purcell in the late seventies. We re-examine their work in order to assess what insight it may offer for making efficient, practical biosensors. We model the functioning of a typical biosensor as a reaction-diffusion process in a confined geometry. Using available data first we characterize the system by estimating the kinetic constants for the binding and unbinding reactions between the chemoattractants and the receptors. Then we compute the binding flux for this system, which Berg and Purcell had discussed. Unlike in microorganisms where the interval between successive measurements determines the efficiency of the nutrient searching process, it turns out that biosensors depend on long time properties like signal saturation time, which we study in detail. We also develop a mean field description of the kinetics of the system.

  12. Sterilization of Microorganisms by Ozone and Ultrasound

    NASA Astrophysics Data System (ADS)

    Krasnyj, V. V.; Klosovskij, A. V.; Panasko, T. A.; Shvets, O. M.; Semenova, O. T.; Taran, V. S.; Tereshin, V. I.

    2008-03-01

    The results of recent experimental methods of sterilization of microorganisms with the use of ozone and ultrasound are presented. The main aim was to optimize the process of sterilization in water solution taking into account the ozone concentration, the power of ultrasonic emitter and the temperature of water. In the present work, the ultrasonic cavitation with simultaneous ozone generation has been used. The high ozone concentration in water solution was achieved by two-barrier glow discharge generated at atmospheric pressure and a cooling thermo-electric module. Such a sterilizer consists of ozone generator in a shape of flat electrodes covered with dielectric material and a high-voltage pulsed power supply of 250 W. The sterilization camera was equipped with ultrasonic source operated at 100 W. The experiments on the inactivation of bacteria of the Bacillus Cereus type were carried out in the distilled water saturated by ozone. The ozone concentration in the aqueous solution was 10 mg/1, whereas the ozone concentration at the output of ozone generator was 30 mg/1. The complete inactivation of spores took 15 min. Selection of the temperature of water, the ozone concentrations and ultrasonic power allowed to determine the time necessary for destroying the row of microorganisms.

  13. Do Killing-Yano tensors form a Lie Algebra?

    E-print Network

    David Kastor; Sourya Ray; Jennie Traschen

    2007-05-03

    Killing-Yano tensors are natural generalizations of Killing vectors. We investigate whether Killing-Yano tensors form a graded Lie algebra with respect to the Schouten-Nijenhuis bracket. We find that this proposition does not hold in general, but that it does hold for constant curvature spacetimes. We also show that Minkowski and (anti)-deSitter spacetimes have the maximal number of Killing-Yano tensors of each rank and that the algebras of these tensors under the SN bracket are relatively simple extensions of the Poincare and (A)dS symmetry algebras.

  14. Advancements in dynamic kill calculations for blowout wells

    SciTech Connect

    Kouba, G.E. (Chevron Petroleum Technology Co., La Habra, CA (United States). Production Fluids Div.); MacDougall, G.R. (Chevron Canada Resources Ltd., Slave Lake, (Canada)); Schumacher, B.W. (Chevron Petroleum Technology Co., Houston, TX (United States). Information Technology Dept.)

    1993-09-01

    This paper addresses the development, interpretation, and use of dynamic kill equations. To this end, three simple calculation techniques are developed for determining the minimum dynamic kill rate. Two techniques contain only single-phase calculations and are independent of reservoir inflow performance. Despite these limitations, these two methods are useful for bracketing the minimum flow rates necessary to kill a blowing well. For the third technique, a simplified mechanistic multiphase-flow model is used to determine a most-probable minimum kill rate.

  15. 43 CFR 3873.3 - Non-mineral entry of residue of subdivisions invaded by mining claims.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Non-mineral entry of residue of subdivisions invaded by mining claims. 3873...contest, or by approved mining claims of established mineral character, the authorized...are asserted to be mineral, or mining locations,...

  16. Killing of Leishmania parasites in activated murine macrophages is based on an L-arginine-dependent process that produces nitrogen derivatives

    SciTech Connect

    Maul, J.R.; Ransijn, A.; Buchmueller-Rouiller, Y. (Institute of Biochemistry, Epalinges (Switzerland))

    1991-01-01

    The experiments described in this report were aimed at determining whether L-arginine (L-arg)-derived nitrogen oxidation products (nitric oxide, nitrous acid, nitrites) are involved in the intracellular killing of Leishmania parasites by activated murine macrophages in vitro. Peritoneal or bone marrow-derived macrophages were infected with L. enriettii or L. major, then activated by exposure to recombinant murine interferon-gamma or to macrophage activating factor (MAF)-rich media in the presence of lipopolysaccharide. Activation of macrophages in regular (i.e., arginine-containing) culture medium led to complete destruction of the microorganisms within 24 h (L. enriettii) or 48 h (L. major), concomitant with accumulation of nitrites (NO2-) in the culture fluids. When macrophage activation was carried out in L-arg-free medium, however, neither parasite killing nor NO2- production was obtained. A similar inhibition of macrophage leishmanicidal activity and of NO2- release was observed using media treated with arginase (which converts L-arg to urea and ornithine), or supplemented with NG-monomethyl-L-arg or guanidine (which inhibit the conversion of L-arg to nitrogen oxidation products). In all these situations, an excellent correlation between the levels of NO2- production by macrophages and intracellular killing of Leishmania was observed, whereas no strict correlation was detectable between leishmanicidal activity and superoxide production. Intracellular parasite killing by activated macrophages could be prevented by addition of iron salts to the incubation fluids. Incubation of free parasites with NaNO2 at acid pH led to immobilisation, multiplication arrest, and morphological degeneration of the microorganisms. Similarly, exposure of infected cells to NaNO2 led to killing of the intracellular parasite without affecting macrophage viability.

  17. Reduction of Contaminated Microorganisms in Dried Bananas with Ozone

    Microsoft Academic Search

    Nakorn Pathom

    The aims of this research were to investigate the t ypes and numbers of contaminated micro-organisms in solar-dried bananas and the use of ozone to extend shelf-life of dried bananas. Commercial dried banan a samples were collected from different areas to examine the types and numbers of total microorganisms, yeast and mould counts. Microorganisms were identified to genus from their

  18. Geometry of Killing spinors in neutral signature

    E-print Network

    Klemm, Dietmar

    2015-01-01

    We classify the supersymmetric solutions of minimal $N=2$ gauged supergravity in four dimensions with neutral signature. They are distinguished according to the sign of the cosmological constant and whether the vector field constructed as a bilinear of the Killing spinor is null or non-null. In neutral signature the bilinear vector field can be spacelike, which is a new feature not arising in Lorentzian signature. In the $\\Lambda0$ non-null case, the manifold is a fibration over a Lorentzian Gauduchon-Tod base space. Finally, in the $\\Lambda>0$ null class, the metric is contained in the Kundt family, and it turns out that the holonomy is reduced to ${\\rm Sim}(1)\\times{\\rm Sim}(1)$. There appear no self-dual solutions in the null class for either sign of the cosmological constant.

  19. Killing Reduction of 5-Dimensional Spacetimes

    E-print Network

    Xuejun Yang; Yongge Ma; Jianbing Shao; Wei Zhou

    2003-07-25

    In a 5-dimensional spacetime ($M,g_{ab}$) with a Killing vector field $\\xi ^a$ which is either everywhere timelike or everywhere spacelike, the collection of all trajectories of $\\xi ^a$ gives a 4-dimensional space $S$. The reduction of ($M,g_{ab}$) is studied in the geometric language, which is a generalization of Geroch's method for the reduction of 4-dimensional spacetime. A 4-dimensional gravity coupled to a vector field and a scalar field on $S$ is obtained by the reduction of vacuum Einstein's equations on $M$, which gives also an alternative description of the 5-dimensional Kaluza-Klein theory. Besides the symmetry-reduced action from the Hilbert action on $M$, an alternative action of the fields on $S$ is also obtained, the variations of which lead to the same fields equations as those reduced from the vacuum Einstein equation on $M$.

  20. 21 CFR 866.2660 - Microorganism differentiation and identification device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2660 Microorganism differentiation and identification device. (a)...

  1. 21 CFR 866.2660 - Microorganism differentiation and identification device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2660 Microorganism differentiation and identification device. (a)...

  2. 21 CFR 866.2660 - Microorganism differentiation and identification device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2660 Microorganism differentiation and identification device. (a)...

  3. 21 CFR 866.2660 - Microorganism differentiation and identification device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2660 Microorganism differentiation and identification device. (a)...

  4. 21 CFR 866.2660 - Microorganism differentiation and identification device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2660 Microorganism differentiation and identification device. (a)...

  5. POLYPEPTIDE AND POLYSACCHARIDE PROCESSING IN HYPERTHERMOPHILIC MICROORGANISMS

    SciTech Connect

    KELLY, ROBERT M.

    2008-12-22

    This project focused on the microbial physiology and biochemistry of heterotrophic hyperthermophiles with respect to mechanisms by which these organisms process polypeptides and polysaccharides under normal and stressed conditions. Emphasis is on two model organisms, for which completed genome sequences are available: Pyrococcus furiosus (growth Topt of 98°C), an archaeon, and Thermotoga maritima (growth Topt of 80°C), a bacterium. Both organisms are obligately anaerobic heterotrophs that reduce sulfur facultatively. Whole genome cDNA spotted microarrays were used to follow transcriptional response to a variety of environmental conditions in order to identify genes encoding proteins involved in the acquisition, synthesis, processing and utilization of polypeptides and polysaccharides. This project provided new insights into the physiological aspects of hyperthermophiles as these relate to microbial biochemistry and biological function in high temperature habitats. The capacity of these microorganisms to produce biohydrogen from renewable feedstocks makes them important for future efforts to develop biofuels.

  6. Genetic engineering of microorganisms for biodiesel production

    PubMed Central

    Lin, Hui; Wang, Qun; Shen, Qi; Zhan, Jumei; Zhao, Yuhua

    2013-01-01

    Biodiesel, as one type of renewable energy, is an ideal substitute for petroleum-based diesel fuel and is usually made from triacylglycerides by transesterification with alcohols. Biodiesel production based on microbial fermentation aiming to establish more efficient, less-cost and sustainable biodiesel production strategies is under current investigation by various start-up biotechnology companies and research centers. Genetic engineering plays a key role in the transformation of microbes into the desired cell factories with high efficiency of biodiesel production. Here, we present an overview of principal microorganisms used in the microbial biodiesel production and recent advances in metabolic engineering for the modification required. Overexpression or deletion of the related enzymes for de novo synthesis of biodiesel is highlighted with relevant examples. PMID:23222170

  7. Male Brown-headed Cowbird Attacks and Kills a Nestling

    USGS Publications Warehouse

    Igl, L.D.

    2003-01-01

    I observed a male Brown-headed Cowbird (Molothrus ater) attack and kill a nestling of an unidentified passerine in a grassland field in Day County, South Dakota, in June 2000. The killing or removal of nestlings by female cowbirds has been reported by others, but this behavior has not been documented previously in male cowbirds.

  8. 7. LOOKING WEST TOWARD SHEEP KILL AREA ON SOUTH END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. LOOKING WEST TOWARD SHEEP KILL AREA ON SOUTH END OF BUILDING 149; INCLINED CONVEYOR AT LEFT CENTER CARRIED TROLLEYS TO THE AUTOMATIC WASHER/OILER ON THE GALLERY LEVEL - Rath Packing Company, Beef Killing Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  9. 9. GENERAL INTERIOR VIEW OF BEEF KILLING FLOOR; LOOKING SOUTHEAST; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. GENERAL INTERIOR VIEW OF BEEF KILLING FLOOR; LOOKING SOUTHEAST; PLATFORMS IN FOREGROUND WERE USED BY SPLITTERS, TRIMMERS AND GOVERNMENT INSPECTORS; SKINNING TABLE RAN ALONG THE WINDOWS NEAR THE CENTER OF THE PHOTO - Rath Packing Company, Beef Killing Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  10. Microwave irradiation for rapid killing and fixing of plant tissue

    SciTech Connect

    Walsh, G.E.; Bohannon, P.M.; Wessinger-Duvall, P.B.

    1989-01-01

    Irradiation by microwaves allows for rapid killing and fixing of plant tissue, with excellent cellular integrity for histological examination. One or two exposures to microwaves for three seconds in formalin/acetic acid/alcohol gave good preservation of nuclei, chloroplasts, and other plant structures. The microwave method offers a considerable saving of time over traditional methods for killing and fixing plant tissue.

  11. Rickettsia associated with male-killing in a buprestid beetle

    E-print Network

    Werren, John H.

    bacterium that causes male-killing in an unrelated ladybird beetle species. Low levels of parthenogenesisRickettsia associated with male-killing in a buprestid beetle EILLEEN T. LAWSON , TIMOTHY A populations of the buprestid leaf-mining beetle, Brachys tessellatus, from central South Carolina, USA, show

  12. Quaternionic Killing Spinors W. Kramer*, U. Semmelmanny, G. Weingartz

    E-print Network

    Weingart, Gregor

    Quaternionic Killing Spinors W. Kramer*, U bound for the spectrum of the Dirac opera* *tor on quaternionic K"ahler manifolds. In the present as an eigenvalue. We give an equivalent formulation in terms of a* * quaternionic Killing equation and show

  13. Quasistationary distributions for one-dimensional diffusions with killing

    Microsoft Academic Search

    David Steinsaltz; Steven N. Evans

    2004-01-01

    We extend some results on the convergence of one-dimensional diffusions killed at the boundary, conditioned on extended survival, to the case of general killing on the interior. We show, under fairly general conditions, that a diffusion conditioned on long survival either runs off to infinity almost surely, or almost surely converges to a quasistationary distribution given by the lowest eigenfunction

  14. Controlling the Pine-Killing Woodwasp, Sirex noctilio, with Nematodes

    E-print Network

    Chapter 12 Controlling the Pine-Killing Woodwasp, Sirex noctilio, with Nematodes Robin A. Bedding Abstract The pine-killing woodwasp Sirex noctilio, a native to Eurasia/Morocco, was accidentally introduced are described for liberating nematodes in pine plantations. The nematode has caused major crashes in S. noctilio

  15. Pseudomonas aeruginosa PAO1 Kills Caenorhabditis elegans by Cyanide Poisoning

    Microsoft Academic Search

    LARRY A. GALLAGHER; COLIN MANOIL

    2001-01-01

    In this report we describe experiments to investigate a simple virulence model in which Pseudomonas aerugi- nosa PAO1 rapidly paralyzes and kills the nematode Caenorhabditis elegans. Our results imply that hydrogen cyanide is the sole or primary toxic factor produced by P. aeruginosa that is responsible for killing of the nematode. Four lines of evidence support this conclusion. First, a

  16. PDE5 Inhibitors Enhance Celecoxib Killing in Multiple Tumor Types

    PubMed Central

    BOOTH, LAURENCE; ROBERTS, JANE L.; CRUICKSHANKS, NICHOLA; TAVALLAI, SEYEDMEHRAD; WEBB, TIMOTHY; SAMUEL, PETER; CONLEY, ADAM; BINION, BRITTANY; YOUNG, HAROLD F.; POKLEPOVIC, ANDREW; SPIEGEL, SARAH; DENT, PAUL

    2015-01-01

    The present studies determined whether clinically relevant phosphodiesterase 5 (PDE5) inhibitors interacted with a clinically relevant NSAID, celecoxib, to kill tumor cells. Celecoxib and PDE5 inhibitors interacted in a greater than additive fashion to kill multiple tumor cell types. Celecoxib and sildenafil killed ex vivo primary human glioma cells as well as their associated activated microglia. Knock down of PDE5 recapitulated the effects of PDE5 inhibitor treatment; the nitric oxide synthase inhibitor L-NAME suppressed drug combination toxicity. The effects of celecoxib were COX2 independent. Over-expression of c-FLIP-s or knock down of CD95/FADD significantly reduced killing by the drug combination. CD95 activation was dependent on nitric oxide and ceramide signaling. CD95 signaling activated the JNK pathway and inhibition of JNK suppressed cell killing. The drug combination inactivated mTOR and increased the levels of autophagy and knock down of Beclin1 or ATG5 strongly suppressed killing by the drug combination. The drug combination caused an ER stress response; knock down of IRE1?/XBP1 enhanced killing whereas knock down of eIF2?/ATF4/CHOP suppressed killing. Sildenafil and celecoxib treatment suppressed the growth of mammary tumors in vivo. Collectively our data demonstrate that clinically achievable concentrations of celecoxib and sildenafil have the potential to be a new therapeutic approach for cancer. PMID:25303541

  17. Synergy of human neutrophils with fluconazole in killing Candida species.

    PubMed

    Brummer, E; Stevens, D A

    1996-01-01

    The killing of Candida species by human neutrophils in a long-term 24-h assay and possible synergy with fluconazole (FCZ) for killing was investigated. The test medium (TM) consisted of RPMI-1640, penicillin and streptomycin (P/S), and 10% fresh autologous serum. TM alone was highly fungistatic for Candida species compared to TM without serum. When neutrophils were cocultured in TM with Candida species for 24 h the inoculum colony-forming units (CFU) were always significantly reduced (killing) by 58 to 99%. FCZ was tested over a range of 1-500 micrograms/ml, and though almost always fungistatic itself, it synergized with neutrophils for significantly increased killing of C. albicans (isolate Sh27) (P < 0.01) and C. albicans (isolate 94-20) (P < 0.05). Killing of non-albicans Candida species was so efficient in the absence of FCZ that demonstration of synergy with FCZ was difficult. PMID:8981777

  18. KILLING FORMS ON G2 AND Spin7MANIFOLDS UWE SEMMELMANN

    E-print Network

    Semmelmann, Uwe

    KILLING FORMS ON G2­ AND Spin7­MANIFOLDS UWE SEMMELMANN Abstract. Killing forms on Riemannian that on a compact manifold with holonomy G2 or Spin7 any Killing form has to be parallel. The main tool, 58J50 1. Introduction Killing forms are a natural generalization of Killing vector fields

  19. Enterococcus faecalis Subverts and Invades the Host Urothelium in Patients with Chronic Urinary Tract Infection

    PubMed Central

    Horsley, Harry; Malone-Lee, James; Holland, David; Tuz, Madeleine; Hibbert, Andrew; Kelsey, Michael; Kupelian, Anthony; Rohn, Jennifer L.

    2013-01-01

    Bacterial urinary tract infections (UTI) are a major growing concern worldwide. Uropathogenic Escherichia coli has been shown to invade the urothelium during acute UTI in mice and humans, forming intracellular reservoirs that can evade antibiotics and the immune response, allowing recurrence at a later date. Other bacterial species, such as Staphylococcus saprophyticus, Klebsiella pneumonia and Salmonella enterica have also been shown to be invasive in acute UTI. However, the role of intracellular infection in chronic UTI causing more subtle lower urinary tract symptoms (LUTS), a particular problem in the elderly population, is poorly understood. Moreover, the species of bacteria involved remains largely unknown. A previous study of a large cohort of non-acute LUTS patients found that Enterococcus faecalis was frequently found in urine specimens. E. faecalis accounts for a significant proportion of chronic bladder infections worldwide, although the invasive lifestyle of this uropathogen has yet to be reported. Here, we wanted to explore this question in more detail. We harvested urothelial cells shed in response to inflammation and, using advanced imaging techniques, inspected them for signs of bacterial pathology and invasion. We found strong evidence of intracellular E. faecalis harboured within urothelial cells shed from the bladder of LUTS patients. Furthermore, using a culture model system, these patient-isolated strains of E. faecalis were able to invade a transitional carcinoma cell line. In contrast, we found no evidence of cellular invasion by E. coli in the patient cells or the culture model system. Our data show that E. faecalis is highly competent to invade in this context; therefore, these results have implications for both the diagnosis and treatment of chronic LUTS. PMID:24363814

  20. Epiphyte Water Retention and Evaporation in Native and Invaded Tropical Montane Cloud Forests in Hawaii

    NASA Astrophysics Data System (ADS)

    Mudd, R. G.; Giambelluca, T. W.

    2006-12-01

    Epiphyte water retention was quantified at two montane cloud forest sites in Hawai'i Volcanoes National Park, one native and the other invaded by an alien tree species. Water storage elements measured included all epiphytic mosses, leafy liverworts, and filmy ferns. Tree surface area was estimated and a careful survey was taken to account for all epiphytes in the sample area of the forest. Samples were collected and analyzed in the lab for epiphyte water retention capacity (WRC). Based on the volume of the different kinds of epiphytes and their corresponding WRC, forest stand water retention capacity for each survey area was estimated. Evaporation from the epiphyte mass was quantified using artificial reference samples attached to trees that were weighed at intervals to determine changes in stored water on days without significant rain or fog. In addition, a soil moisture sensor was wrapped in an epiphyte sample and left in the forest for a 6-day period. Epiphyte biomass at the Native Site and Invaded Site were estimated to be 2.89 t ha-1 and 1.05 t ha-1, respectively. Average WRC at the Native Site and Invaded Site were estimated at 1.45 mm and 0.68 mm, respectively. The difference is likely due to the presence of the invasive Psidium cattleianum at the Invaded Site because its smooth stem surface is unable to support a significant epiphytic layer. The evaporation rate from the epiphyte mass near WSC for the forest stand at the Native Site was measured at 0.38 mm day-1, which represented 10.6 % of the total ET from the forest canopy at the Native Site during the period. The above research has been recently complemented by a thorough investigation of the WSC of all water storage elements (tree stems, tree leaves, shrubs, grasses, litter, fallen branches, and epiphytes) at six forested sites at different elevations within, above, and below the zone of frequent cloud-cover. The goal of this study was to create an inexpensive and efficient methodology for acquiring estimates of above-ground water retention in different types of forests by means of minimally-destructive sampling and surveying. The results of this work serve as baseline data providing a range of possible values of the water retention of specific forest elements and the entire above-ground total where no values have been previously recorded.

  1. On pseudo-Riemannian manifolds with many Killing spinors

    SciTech Connect

    Alekseevsky, D. V. [University of Edinburgh and Maxwell Institute for Mathematical Sciences JCMB, The King's Buildings, Edinburgh, EH9 3JZ (United Kingdom); Cortes, V. [Department Mathematik und Zentrum fuer Mathematische Physik Universitaet Hamburg, Bundesstrasse 55, D-20146 Hamburg (Germany)

    2009-02-02

    Let M be a pseudo-Riemannian spin manifold of dimension n and signature s and denote by N the rank of the real spinor bundle. We prove that M is locally homogeneous if it admits more than (3/4)N independent Killing spinors with the same Killing number, unless n {identical_to} 1(mod 4) and s {identical_to} 3(mod 4). We also prove that M is locally homogeneous if it admits k{sub +} independent Killing spinors with Killing number {lambda} and k{sub -} independent Killing spinors with Killing number -{lambda} such that k{sub +}+k{sub -}>(3/2)N, unless n {identical_to} s {identical_to} 3(mod 4). Similarly, a pseudo-Riemannian manifold with more than (3/4)N independent conformal Killing spinors is conformally locally homogeneous. For (positive or negative) definite metrics, the bounds (3/4)N and (3/2)N in the above results can be relaxed to (1/2)N and N, respectively. Furthermore, we prove that a pseudo-Riemannnian spin manifold with more than (3/4)N parallel spinors is flat and that (1/4)N parallel spinors suffice if the metric is definite. Similarly, a Riemannnian spin manifold with more than (3/8)N Killing spinors with the Killing number {lambda}(set-membership sign)R has constant curvature 4{lambda}{sup 2}. For Lorentzian or negative definite metrics the same is true with the bound (1/2)N. Finally, we give a classification of (not necessarily complete) Riemannian manifolds admitting Killing spinors, which provides an inductive construction of such manifolds.

  2. Managing Threat, Cost, and Incentive to Kill: The Short- and Long-Term Effects of Intervention in Mass Killings

    ERIC Educational Resources Information Center

    Kathman, Jacob D.; Wood, Reed M.

    2011-01-01

    How do third-party interventions affect the severity of mass killings? The authors theorize that episodes of mass killing are the consequence of two factors: (1) the threat perceptions of the perpetrators and (2) the cost of implementing genocidal policies relative to other alternatives. To reduce genocidal hostilities, interveners must address…

  3. The use of stable isotope ratio analysis to distinguish multiple prey kill events from mass kill events

    Microsoft Academic Search

    Jack N. Fenner

    2008-01-01

    Archaeologists working with prey animal bonebeds are interested in determining whether the animals were obtained through a single, mass kill event or instead accumulated over time from multiple hunting events. This is often difficult to determine. The author investigated the use of stable isotope ratio analysis to distinguish accumulations of individuals derived from multiple populations from mass kills of individuals

  4. Campylobacter jejuni Actively Invades the Amoeba Acanthamoeba polyphaga and Survives within Non Digestive Vacuoles

    PubMed Central

    Olofsson, Jenny; Axelsson-Olsson, Diana; Brudin, Lars; Olsen, Björn; Ellström, Patrik

    2013-01-01

    The Gram-negative bacterium Campylobacter jejuni is able to enter, survive and multiply within the free living amoeba Acanthamoeba polyphaga, but the molecular mechanisms behind these events are still unclear. We have studied the uptake and intracellular trafficking of viable and heat killed bacterial cells of the C. jejuni strain 81–176 in A. polyphaga. We found that viable bacteria associated with a substantially higher proportion of Acanthamoeba trophozoites than heat killed bacteria. Furthermore, the kinetics of internalization, the total number of internalized bacteria as well as the intracellular localization of internalized C. jejuni were dramatically influenced by bacterial viability. Viable bacteria were internalized at a high rate already after 1 h of co-incubation and were observed in small vacuoles tightly surrounding the bacteria. In contrast, internalization of heat killed C. jejuni was low at early time points and did not peak until 96 h. These cells were gathered in large spacious vacuoles that were part of the degradative pathway as determined by the uptake of fluorescently labeled dextran. The amount of heat killed bacteria internalized by A. polyphaga did never reach the maximal amount of internalized viable bacteria. These results suggest that the uptake and intracellular survival of C. jejuni in A. polyphaga is bacterially induced. PMID:24223169

  5. MICROORGANISMS IN MUNICIPAL SOLID WASTE AND PUBLIC HEALTH IMPLICATIONS

    EPA Science Inventory

    The composition of municipal solid waste is quite heterogeneous. This mixed composition results in the presence of a variety of microorganisms that reach densities which are relatively high, and which remain high even after many years in a landfill. Microorganism densities in the...

  6. Capillary isoelectric focusing of native and inactivated microorganisms

    Microsoft Academic Search

    M. Horká; O. Kubí?ek; F. R?ži?ka; V. Holá; I. Malinovská; K. Šlais

    2007-01-01

    The research of microorganisms includes the development of methods for the inactivation of viruses and other microbes. It also means to efficiently eliminate the infectivity of microorganisms without damage of their integrity and structure. According to the results of the last 5 years the capillary electromigration techniques appear to be very perspective for the comparison of the methods applicable for

  7. Glochidioboside Kills Pathogenic Bacteria by Membrane Perturbation.

    PubMed

    Lee, Heejeong; Woo, Eun-Rhan; Lee, Dong Gun

    2015-07-01

    The aim of this study was to evaluate the antibacterial effects of glochidioboside and determine its mechanism of action. Glochidioboside has been reported to be isolated from some plants but the underlying biological properties have remained largely obscure until now. To identify the antibacterial activity of all biological properties, pathogenic bacteria susceptibility test was performed, and the result shows that the compound displays remarkable antibacterial activity against antibiotic-resistant bacteria not to mention general pathogen. To demonstrate membrane disruption and depolarization, SYTOX green and bis-(1,3-dibutylbarbituric acid) trimethine oxonol were used with Escherichia coli O157, and indicated that glochidioboside affected cytoplasmic membranes by permeabilization and depolarization, respectively. Calcein efflux was evident in a membrane model that encapsulated fluorescent dye, and supported the hypothesis of a membrane-active mechanism. To confirm the release of intracellular matrix owing to membrane damage, the movements of potassium ion were observed; the results indicated that the cells treated with glochidioboside leaked potassium ion, thus the damage induced by the compounds lead to leaking intracellular components. We propose that glochidioboside kills pathogenic bacteria via perturbation of integrity of the membrane. PMID:25820208

  8. Combinatorial stresses kill pathogenic Candida species.

    PubMed

    Kaloriti, Despoina; Tillmann, Anna; Cook, Emily; Jacobsen, Mette; You, Tao; Lenardon, Megan; Ames, Lauren; Barahona, Mauricio; Chandrasekaran, Komelapriya; Coghill, George; Goodman, Daniel; Gow, Neil A R; Grebogi, Celso; Ho, Hsueh-Lui; Ingram, Piers; McDonagh, Andrew; de Moura, Alessandro P S; Pang, Wei; Puttnam, Melanie; Radmaneshfar, Elahe; Romano, Maria Carmen; Silk, Daniel; Stark, Jaroslav; Stumpf, Michael; Thiel, Marco; Thorne, Thomas; Usher, Jane; Yin, Zhikang; Haynes, Ken; Brown, Alistair J P

    2012-10-01

    Pathogenic microbes exist in dynamic niches and have evolved robust adaptive responses to promote survival in their hosts. The major fungal pathogens of humans, Candida albicans and Candida glabrata, are exposed to a range of environmental stresses in their hosts including osmotic, oxidative and nitrosative stresses. Significant efforts have been devoted to the characterization of the adaptive responses to each of these stresses. In the wild, cells are frequently exposed simultaneously to combinations of these stresses and yet the effects of such combinatorial stresses have not been explored. We have developed a common experimental platform to facilitate the comparison of combinatorial stress responses in C. glabrata and C. albicans. This platform is based on the growth of cells in buffered rich medium at 30°C, and was used to define relatively low, medium and high doses of osmotic (NaCl), oxidative (H(2)O(2)) and nitrosative stresses (e.g., dipropylenetriamine (DPTA)-NONOate). The effects of combinatorial stresses were compared with the corresponding individual stresses under these growth conditions. We show for the first time that certain combinations of combinatorial stress are especially potent in terms of their ability to kill C. albicans and C. glabrata and/or inhibit their growth. This was the case for combinations of osmotic plus oxidative stress and for oxidative plus nitrosative stress. We predict that combinatorial stresses may be highly significant in host defences against these pathogenic yeasts. PMID:22463109

  9. Curvilinear effects of invasive plants on plant diversity: plant community invaded by Sphagneticola trilobata.

    PubMed

    Qi, Shan-Shan; Dai, Zhi-Cong; Zhai, De-Li; Chen, Si-Chong; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Zhong, Qiong-Xin; Du, Dao-Lin

    2014-01-01

    The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants. PMID:25426856

  10. Integrating novel chemical weapons and evolutionarily increased competitive ability in success of a tropical invader.

    PubMed

    Zheng, Yu-Long; Feng, Yu-Long; Zhang, Li-Kun; Callaway, Ragan M; Valiente-Banuet, Alfonso; Luo, Du-Qiang; Liao, Zhi-Yong; Lei, Yan-Bao; Barclay, Gregor F; Silva-Pereyra, Carlos

    2015-02-01

    The evolution of increased competitive ability (EICA) hypothesis and the novel weapons hypothesis (NWH) are two non-mutually exclusive mechanisms for exotic plant invasions, but few studies have simultaneously tested these hypotheses. Here we aimed to integrate them in the context of Chromolaena odorata invasion. We conducted two common garden experiments in order to test the EICA hypothesis, and two laboratory experiments in order to test the NWH. In common conditions, C. odorata plants from the nonnative range were better competitors but not larger than plants from the native range, either with or without the experimental manipulation of consumers. Chromolaena odorata plants from the nonnative range were more poorly defended against aboveground herbivores but better defended against soil-borne enemies. Chromolaena odorata plants from the nonnative range produced more odoratin (Eupatorium) (a unique compound of C. odorata with both allelopathic and defensive activities) and elicited stronger allelopathic effects on species native to China, the nonnative range of the invader, than on natives of Mexico, the native range of the invader. Our results suggest that invasive plants may evolve increased competitive ability after being introduced by increasing the production of novel allelochemicals, potentially in response to naïve competitors and new enemy regimes. PMID:25367824

  11. Curvilinear Effects of Invasive Plants on Plant Diversity: Plant Community Invaded by Sphagneticola trilobata

    PubMed Central

    Zhai, De-Li; Chen, Si-Chong; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Zhong, Qiong-Xin; Du, Dao-Lin

    2014-01-01

    The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants. PMID:25426856

  12. Citrus leaf blotch virus invades meristematic regions in Nicotiana benthamiana and citrus.

    PubMed

    Agüero, Jesús; Vives, María Carmen; Velázquez, Karelia; Ruiz-Ruiz, Susana; Juárez, Jose; Navarro, Luis; Moreno, Pedro; Guerri, José

    2013-08-01

    To invade systemically host plants, viruses need to replicate in the infected cells, spread to neighbouring cells through plasmodesmata and move to distal parts of the plant via sieve tubes to start new infection foci. To monitor the infection of Nicotiana benthamiana plants by Citrus leaf blotch virus (CLBV), leaves were agroinoculated with an infectious cDNA clone of the CLBV genomic RNA expressing green fluorescent protein (GFP) under the transcriptional control of a duplicate promoter of the coat protein subgenomic RNA. Fluorescent spots first appeared in agroinfiltrated leaves 11-12 days after infiltration, indicating CLBV replication. Then, after entering the phloem vascular system, CLBV was unloaded in the upper parts of the plant and invaded all tissues, including flower organs and meristems. GFP fluorescence was not visible in citrus plants infected with CLBV-GFP. Therefore, to detect CLBV in meristematic regions, Mexican lime (Citrus aurantifolia) plants were graft inoculated with CLBV, with Citrus tristeza virus (CTV), a virus readily eliminated by shoot-tip grafting in?vitro, or with both simultaneously. Although CLBV was detected by hybridization and real-time reverse transcription-polymerase chain reaction (RT-PCR) in 0.2-mm shoot tips in all CLBV-inoculated plants, CTV was not detected. These results explain the difficulty in eliminating CLBV by shoot-tip grafting in?vitro. PMID:23560714

  13. Generalized Killing-Yano equations in D=5 gauged supergravity

    NASA Astrophysics Data System (ADS)

    Kubiz?ák, David; Kunduri, Hari K.; Yasui, Yukinori

    2009-07-01

    We propose a generalization of the (conformal) Killing-Yano equations relevant to D=5 minimal gauged supergravity. The generalization stems from the fact that the dual of the Maxwell flux, the 3-form ?F, couples naturally to particles in the background as a ‘torsion’. Killing-Yano tensors in the presence of torsion preserve most of the properties of the standard Killing-Yano tensors — exploited recently for the higher-dimensional rotating black holes of vacuum gravity with cosmological constant. In particular, the generalized closed conformal Killing-Yano 2-form gives rise to the tower of generalized closed conformal Killing-Yano tensors of increasing rank which in turn generate the tower of Killing tensors. An example of a generalized Killing-Yano tensor is found for the Chong-Cveti?-Lü-Pope black hole spacetime [Z.W. Chong, M. Cvetic, H. Lu, C.N. Pope, hep-th/0506029]. Such a tensor stands behind the separability of the Hamilton-Jacobi, Klein-Gordon, and Dirac equations in this background.

  14. Protein chlorination in neutrophil phagosomes and correlation with bacterial killing.

    PubMed

    Green, Jessie N; Kettle, Anthony J; Winterbourn, Christine C

    2014-12-01

    Neutrophils ingest and kill bacteria within phagocytic vacuoles. We investigated where they produce hypochlorous acid (HOCl) following phagocytosis by measuring conversion of protein tyrosine residues to 3-chlorotyrosine. We also examined how varying chloride availability affects the relationship between HOCl formation in the phagosome and bacterial killing. Phagosomal proteins, isolated following ingestion of opsonized magnetic beads, contained 11.4 Cl-Tyr per thousand tyrosine residues. This was 12 times higher than the level in proteins from the rest of the neutrophil and ~6 times higher than previously recorded for protein from ingested bacteria. These results indicate that HOCl production is largely localized to the phagosomes and a substantial proportion reacts with phagosomal protein before reaching the microbe. This will in part detoxify the oxidant but should also form chloramines which could contribute to the killing mechanism. Neutrophils were either suspended in chloride-free gluconate buffer or pretreated with formyl-Met-Leu-Phe, a procedure that has been reported to deplete intracellular chloride. These treatments, alone or in combination, decreased both chlorination in phagosomes and killing of Staphylococcus aureus by up to 50%. There was a strong positive correlation between the two effects. Killing was predominantly oxidant and myeloperoxidase dependent (88% inhibition by diphenylene iodonium and 78% by azide). These results imply that lowering the chloride concentration limits HOCl production and oxidative killing. They support a role for HOCl generation, rather than an alternative myeloperoxidase activity, in the killing process. PMID:25236747

  15. Effect of bromidehypochlorite bactericides on microorganisms.

    PubMed

    SHERE, L; KELLEY, M J; RICHARDSON, J H

    1962-11-01

    A new principle in compounding stable, granular bactericidal products led to unique combinations of a water-soluble inorganic bromide salt with a hypochlorite-type disinfectant of either inorganic or organic type. Microbiological results are shown for an inorganic bactericide composed of chlorinated trisodium phosphate containing 3.1% "available chlorine" and 2% potassium bromide, and for an organic bactericide formulated from sodium dichloroisocyanurate so as to contain 13.4% "available chlorine" and 8% potassium bromide. Comparison of these products with their nonbromide counterparts are reported for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus lactis, Aerobacter aerogenes, and Proteus vulgaris. Test methods employed were the Chambers test, the A.O.A.C. Germicidal and Detergent Sanitizer-Official test, and the Available Chlorine Germicidal Equivalent Concentration test. The minimal killing concentrations for the bromide-hypochlorite bactericides against this variety of organisms were reduced by a factor 2 to 24 times those required for similar hypochlorite-type disinfectants not containing the bromide. PMID:13977149

  16. Potassium channels mediate killing by human natural killer cells

    SciTech Connect

    Schlichter, L.; Sidell N.; Hagiwara, S.

    1986-01-01

    Human natural killer (NK) cells in peripheral blood spontaneously recognize and kill a wide variety of target cells. It has been suggested that ion channels are involved in the killing process because there is a Ca-dependent stage and because killing by presensitized cytotoxic T lymphocytes, which in many respects resembles NK killing, is associated with changes in K and Na transport in the target cell. Using the whole-cell variation of the patch-clamp technique, the authors found a voltage-dependent potassium (K/sup +/) current in NK cells. The K/sup +/ current was reduced in a dose-dependent manner by the K-channel blockers 4-aminopyridine and quinidine and by the traditional Ca-channel blockers verapamil and Cd/sup 2 +/. They tested the effects of ion-channel blockers on killing of two commonly used target cell lines: K562, which is derived from a human myeloid leukemia, and U937, which is derived from a human histiocytic leukemia. Killing of K562 target cells, determined in a standard /sup 51/Cr-release assay, was inhibited in a dose-dependent manner by verapamil, quinidine, Cd/sup 2 +/, and 4-aminopyridine at concentrations comparable to those that blocked the K/sup +/ current in NK cells. In K562 target cells only a voltage-dependent Na= current was found and it was blocked by concentrations of tetrodotoxin that had no effect on killing. Killing of U937 target cells was also inhibited by the two ion-channel blockers tested, quinidine and verapamil. In this cell line only a small K/sup +/ current was found that was similar to the one in NK cells. The findings show that there are K channels in NK cells and that these channels play a necessary role in the killing process.

  17. Stand Structural Controls on Evapotranspiration in Native and Invaded Tropical Montane Cloud Forest in Hawai'i

    NASA Astrophysics Data System (ADS)

    Giambelluca, T. W.; Delay, J. K.; Asner, G. P.; Martin, R. E.; Nullet, M. A.; Huang, M.; Mudd, R. G.; Takahashi, M.

    2008-12-01

    Tropical montane cloud forests (TMCFs) in Hawai'i are important zones of water input and stores of critically important native plant and animal species. Invasion by alien tree species threatens these forests and may alter the hydrological services they provide. At two TMCF sites in Hawai'i, one within native Metrosideros polymorpha forest and the other at a site heavily invaded by Psidium cattleianum, we are conducting measurements of stand-level evapotranspiration (ET), transpiration (using sapflow techniques), energy balance, and related processes. Previously presented results showed that ET as a function of available energy was 27% higher at the invaded site than the native site, with the difference rising to 53% during dry- canopy periods. In this presentation, mechanisms for the observed higher ET rate at the invaded site are explored. The difference in measured xylem flow velocities of native and alien trees cannot explain the observed stand level ET difference. Tree basal area is lower at the invaded site than the native site, again contrary to the ET difference. However, the alien trees have much smaller stem diameters, on average, than the native trees, with little or no heartwood. Hence, the cross-sectional xylem area is much greater in the invaded stand, facilitating higher transpiration rates. These results demonstrate the importance of stand structural controls on ET and raise questions about whether higher ET is a transient feature of the succession or a persistent characteristic of invasive trees.

  18. Heavy metal removal and recovery using microorganisms

    SciTech Connect

    Wilde, E.W. (Westinghouse Savannah River Co., Aiken, SC (United States)); Benemann, J.R. (Benemann (J.R.), Pinole, CA (United States))

    1991-02-01

    Microorganisms -- bacteria, fungi, and microalgae -- can accumulate relatively large amounts of toxic heavy metals and radionuclides from the environment. These organisms often exhibit specificity for particular metals. The metal content of microbial biomass can be a substantial fraction of total dry weight with concentration factors (metal in dry biomass to metal in solution) exceeding one million in some cases. Both living and inert (dead) microbial biomass can be used to reduce heavy metal concentrations in contaminated waters to very low levels -- parts per billion and even lower. In many respects (e.g. specificity, residual metal concentrations, accumulation factors, and economics) microbial bioremoval processes can be superior to conventional processes, such as ion exchange and caustic (lime or hydroxide) precipitation for heavy metals removal from waste and contaminated waters. Thus, bioremoval could be developed to contribute to the clean-up of wastes at the Savannah River Site (SRS) and other DOE facilities. However, the potential advantages of bioremoval processes must still be developed into practical operating systems. A detailed review of the literature suggests that appropriate bioremoval processes could be developed for the SRS. There is great variability from one biomass source to another in bioremoval capabilities. Bioremoval is affected by pH, other ions, temperature, and many other factors. The biological (living vs. dead) and physical (immobilized vs. dispersed) characteristics of the biomass also greatly affect metal binding. Even subtle differences in the microbial biomass, such as the conditions under which it was cultivated, can have major effects on heavy metal binding.

  19. Rapidly evolving microorganisms with high biofuel tolerance

    NASA Astrophysics Data System (ADS)

    Vyawahare, Saurabh; Zhang, Qiucen; Lang, Wendy; Austin, Robert

    2012-02-01

    Replacing non-renewable energy sources is one of the biggest and most exciting challenges of our generation. Algae and bacteria are poised to become major renewable biofuels if strains can be developed that provide a high,consistent and robust yield of oil. One major stumbling block towards this goal is the lack of tolerance to high concentrations of biofuels like isobutanol. Using traditional bioengineering techniques to remedy this face the hurdle of identifying the correct pathway or gene to modify. But the multiplicity of interactions inside a cell makes it very hard to determine what to modify a priori. Instead, we propose a technology that does not require prior knowledge of the genes or pathways to modify. In our approach that marries microfabrication and ecology, spatial heterogeneity is used as a knob to speed up evolution in the desired direction. Recently, we have successfully used this approach to demonstrate the rapid emergence of bacterial antibiotic resistance in as little as ten hours. Here, we describe our experimental results in developing new strains of micro-organisms with high oil tolerance. Besides biofuel production, our work is also relevant to oil spill clean-ups.

  20. Evaluation of actinide biosorption by microorganisms

    SciTech Connect

    Happel, A.M.

    1996-06-01

    Conventional methods for removing metals from aqueous solutions include chemical precipitation, chemical oxidation or reduction, ion exchange, reverse osmosis, electrochemical treatment and evaporation. The removal of radionuclides from aqueous waste streams has largely relied on ion exchange methods which can be prohibitively costly given increasingly stringent regulatory effluent limits. The use of microbial cells as biosorbants for heavy metals offers a potential alternative to existing methods for decontamination or recovery of heavy metals from a variety of industrial waste streams and contaminated ground waters. The toxicity and the extreme and variable conditions present in many radionuclide containing waste streams may preclude the use of living microorganisms and favor the use of non-living biomass for the removal of actinides from these waste streams. In the work presented here, we have examined the biosorption of uranium by non-living, non-metabolizing microbial biomass thus avoiding the problems associated with living systems. We are investigating biosorption with the long term goal of developing microbial technologies for the remediation of actinides.

  1. Flow sorting of microorganisms for molecular analysis.

    PubMed Central

    Wallner, G; Fuchs, B; Spring, S; Beisker, W; Amann, R

    1997-01-01

    Not only classical cultivation-based methods but also the new molecular approaches may result in incomplete and selective information on the natural diversity of microbial communities. Flow sorting of microorganisms from environmental samples allows the deliberate selection of cell populations of interest from highly diverse systems for molecular analysis. Several cellular parameters that can be measured by flow cytometry are useful as sort criteria. Here, we report sorting of bacteria from activated sludge, lake water, and lake sediment according to differences in light scattering, DNA content, and/or affiliation to certain phylogenetic groups as assessed by fluorescein-labeled, rRNA-targeted oligonucleotide probes. Microscopy of the sorted cells showed that populations of originally low abundance could be strongly enriched by flow sorting (up to 280-fold), depending on the original abundance of the cells of interest and the type of sample sorted. The purity of the cells of interest could be further increased by repeated sorting, but this increase was limited by cell aggregation in the case of activated-sludge samples. It was possible to amplify almost full-length 16S ribosomal DNA (rDNA) fragments from sorted microbial cells by PCR, even after fixation with paraformaldehyde and in situ hybridization. Dot blot hybridization and sequencing demonstrated that most of the amplified rDNA originated from those cells that had been selected for by flow sorting. Comparative analysis of 16S rDNA sequences revealed previously unknown species of magnetotactic or activated-sludge bacteria. PMID:9361408

  2. Uses of irradiation for inactivation of microorganisms

    SciTech Connect

    Brynjolfsson, A.

    1988-01-01

    The lethal effects of radiation on microorganisms was noted soon after the discovery of X rays in 1895. In 1904, it was shown that vegetative bacteria are more sensitive than spores; however, no industrial applications could be made as the radiation sources were too expensive. In the mid-1950s, it became economical and practical to sterilize medical products, and ever since sterilization has been a growing industry. Radiation sterilization technology has made possible users of new materials, such as plastics. Food irradiation is about to take off. Just as there was a resistance to pasteurization of milk when it was first introduced, there will be resistance to radpasteurization. Irradiated foods have been proven safe beyond reasonable doubt. Safety has been established through two independent methods: (1) through the most extensive multigeneration animal feeding studies ever carried out, and (2) by analyzing the radiolytic products formed and the chemical changes that take place when food is irradiated. The possible toxicity of these products has been evaluated by an independent group of toxicologists, who based their evaluation on the results of exposure of these products in large quantities either to humans or to animals.

  3. THE RATE OF KILLING OF CLADOCERANS AT HIGHER TEMPERATURES

    PubMed Central

    Brown, L. A.; Crozier, W. J.

    1927-01-01

    In spite of obvious possible sources of disturbance, the "velocity of killing" of organisms at supranormal temperatures, properly determined, tends to adhere to the Arrhenius equation for relation to temperature. Over certain ranges of temperature the relationship between log velocity of killing and 1/T° abs. is linear. Interpreted as due to the thermal denaturing of protein, it is possible that differences between the temperature characteristics for the killing process in closely related forms may be suggestive in regard to the mechanism of the denaturing. The temperature limits within which the linear relationships appear may be classed among those temperature levels which are critical temperatures for protoplasmic organization. PMID:19872376

  4. Special Killing forms on toric Sasaki-Einstein manifolds

    E-print Network

    Vladimir Slesar; Mihai Visinescu; Gabriel Eduard Vilcu

    2014-09-29

    In this paper we study the interplay between complex coordinates on the Calabi-Yau metric cone and the special Killing forms on the toric Sasaki-Einstein manifold. In the general case we give a procedure to locally construct the special Killing forms. In the final part we exemplify the general scheme in the case of the $5-$dimensional $Y^{p,q}$ spaces, identifying the additional special Killing 2-forms which were previously obtained by the second author of the present paper, but with a different method, in [Mod. Phys. Lett. A 27 (2012) 1250217].

  5. Reducibility of Killing tensors in d>4 NHEK geometry

    NASA Astrophysics Data System (ADS)

    Chernyavsky, Dmitry

    2014-09-01

    An extremal rotating black hole in arbitrary dimension, along with time translations and rotations, possesses a number of hidden symmetries characterized by the second rank Killing tensors. As is known, in the near horizon limit the isometry group of the metric is enhanced to include the conformal factor SO(2,1). It is demonstrated that for the near horizon extremal Kerr (NHEK) geometry in arbitrary dimension one of the Killing tensors decomposes into a quadratic combination of the Killing vectors corresponding to the conformal group, while the remaining ones are functionally independent.

  6. HIV transcription is induced with some forms of cell killing

    SciTech Connect

    Woloschak, G.E. [Argonne National Lab., IL (United States); Schreck, S. [Argonne National Lab., IL (United States)][South Carolina Univ., Columbia, SC (United States). Dept. of Chemistry; Panozzo, J. [Loyola Univ. Medical Center, Maywood, IL (United States); Chang-Liu, C.-M. [Argonne National Lab., IL (United States); Libertin, C.R. [Loyola Univ. Medical Center, Maywood, IL (United States)

    1996-11-01

    Using HeLa cells stably transfected with an HIV-LTR-CAT construct`, we demonstrated a peak in CAT induction that occurs in viable (but not necessarily cell-division-competent) cells 24 h following exposure to some cell-killing agents. {Gamma} rays were the only cell-killing agent which did not induce HIV transcription; this can be attributed to the fact that {gamma}-ray-induced apoptotic death requires function p53, which is missing in HeLa cells. For all other agents, HIV-LTR induction was dose-dependent and correlated with the amount of cell killing that occurred in the culture.

  7. A homogeneous population of lymphokine-activated killer (LAK) cells is incapable of killing virus-, bacteria-, or parasite-infected macrophages.

    PubMed

    Zychlinsky, A; Karim, M; Nonacs, R; Young, J D

    1990-01-01

    Previous reports have suggested a role for natural killer (NK) cells in directly lysing host cells infected with bacteria and other intracellular microorganisms. Here, we determined the inability of a highly homogeneous population of lymphokine activated killer (LAK) cells to kill macrophages infected with the following intracellular parasites: Mycobacterium avium, Listeria monocytogenes, Legionella pneumophila, Toxoplasma gondii, and Trypanosoma cruzi. In parallel cytotoxicity assays, LAK cells lysed the tumor targets YAC-1 and P815 effectively. Furthermore, we were able to demonstrate that influenza-specific cytotoxic T lymphocytes (CTL), but not LAK cells, were efficient killers of influenza virus-infected macrophages. PMID:2104576

  8. Did Vertigo Kill America's Forgotten Astronaut?

    NASA Technical Reports Server (NTRS)

    Bendrick, Gregg A.; Merlin, Peter W.

    2007-01-01

    On November 15, 1967, U.S. Air Force test pilot Major Michael J. Adams was killed while flying the X-15 rocket-propelled research vehicle in a parabolic spaceflight profile. This flight was part of a joint effort with NASA. An electrical short in one of the experiments aboard the vehicle caused electrical transients, resulting in excessive workload by the pilot. At altitude Major Adams inappropriately initiated a flat spin that led to a series of unusual aircraft attitudes upon atmospheric re-entry, ultimately causing structural failure of the airframe. Major Adams was known to experience vertigo (i.e. spatial disorientation) while flying the X-15, but all X-15 pilots most likely experienced vertigo (i.e. somatogravic, or "Pitch-Up", illusion) as a normal physiologic response to the accelerative forces involved. Major Adams probably experienced vertigo to a greater degree than did others, since prior aeromedical testing for astronaut selection at Brooks AFB revealed that he had an unusually high degree of labyrinthine sensitivity. Subsequent analysis reveals that after engine burnout, and through the zenith of the flight profile, he likely experienced the oculoagravic ("Elevator") illusion. Nonetheless, painstaking investigation after the mishap revealed that spatial disorientation (Type II, Recognized) was NOT the cause, but rather, a contributing factor. The cause was in fact the misinterpretation of a dual-use flight instrument (i.e. Loss of Mode Awareness), resulting in confusion between yaw and roll indications, with subsequent flight control input that was inappropriate. Because of the altitude achieved on this flight, Major Adams was awarded Astronaut wings posthumously. Understanding the potential for spatial disorientation, particularly the oculoagravic illusion, associated with parabolic spaceflight profiles, and understanding the importance of maintaining mode awareness in the context of automated cockpit design, are two lessons that have direct application to the commercial space industry today.

  9. On the Lie subalgebra of Killing-Milne and Killing-Cartan vector fields in Newtonian space-time

    E-print Network

    N. Chamel

    2014-12-18

    The Galilean (and more generally Milne) invariance of Newtonian theory allows for Killing vector fields of a general kind, whereby the Lie derivative of a field is not required to vanish but only to be cancellable by some infinitesimal Galilean (respectively Milne) gauge transformation. In this paper, it is shown that both the Killing-Milne vector fields, which preserve the background Newtonian space-time structure, and the Killing-Cartan vector fields, which in addition preserve the gravitational field, form a Lie subalgebra.

  10. Effective dynamics of microorganisms that interact with their own trail

    E-print Network

    W. Till Kranz; Anatolij Gelimson; Ramin Golestanian

    2015-04-26

    Like ants, some microorganisms are known to leave trails on surfaces to communicate. Using a simple phenomenological model for an actively moving particle, we explore how trail-mediated self-interaction could affect the behaviour of individual microorganisms. The effective dynamics of each microorganism takes on the form of a delayed stochastic dynamical equation with the trail interaction appearing in the form of short-term memory. Depending on the strength of the coupling, the dynamics exhibits effective diffusion in both orientation and position, orientational oscillations, and a localization transition with a divergent orientational correlation time.

  11. Swimming of microorganisms viewed from string and membrane theories

    E-print Network

    Kawamura, M; Nojiri, S; Masako Kawamura; Akio Sugamoto; Shin'ichi Nojiri

    1993-01-01

    Swimming of microorganisms is studied from a viewpoint of extended objects (strings and membranes) swimming in the incompressible fluid of low Reynolds number. The flagellated motion is analyzed in two dimensional fluid, by using the method developed in the ciliated motion with the Joukowski transformation. Discussion is given on the conserved charges and the algebra which are associated with the area (volume)- preserving diffeomorphisms giving the swimming motion of microorganisms. It is also suggested that the $N$-point string- and membrane-like amplitudes are useful for studying the collective swimming motion of microorganisms when fluctuation of the vorticity distribution exists in the sticky or rubber-like fluid.

  12. Clostridiumm ljungdahlii, an anaerobic ethanol and acetate producing microorganism

    DOEpatents

    Gaddy, J.L.; Clausen, E.C.

    1992-12-22

    A newly discovered microorganism was isolated in a biologically pure culture and designated Clostridium ljungdahlii, having the identifying characteristics of ATCC No. 49587. Cultured in an aqueous nutrient medium under anaerobic conditions, this microorganism is capable of producing ethanol and acetate from CO and H[sub 2]O and/or CO[sub 2] and H[sub 2] in synthesis gas. Under optimal growth conditions, the microorganism produces acetate in preference to ethanol. Conversely, under non-growth conditions, ethanol production is favored over acetate. 3 figs.

  13. Killing superalgebra deformations of ten-dimensional supergravity backgrounds

    E-print Network

    José Figueroa-O'Farrill; Bert Vercnocke

    2007-08-28

    We explore Lie superalgebra deformations of the Killing superalgebras of some ten-dimensional supergravity backgrounds. We prove the rigidity of the Poincare superalgebras in types I, IIA and IIB, as well as of the Killing superalgebra of the Freund-Rubin vacuum of type IIB supergravity. We also prove rigidity of the Killing superalgebras of the NS5, D0, D3, D4 and D5 branes, whereas we exhibit the possible deformations of the D1, D2, D6 and D7 brane Killing superalgebras, as well as of that of the type II fundamental string solutions. We relate the superalgebra deformations of the D2 and D6 branes to those of the (delocalised) M2 brane and the Kaluza-Klein monopole, respectively. The good behaviour under Kaluza-Klein reduction suggests that the deformed superalgebras ought to have a geometric interpretation.

  14. (M-theory-)Killing spinors on symmetric spaces

    E-print Network

    Hustler, Noel

    2015-01-01

    We show how the theory of invariant principal bundle connections for reductive homogeneous spaces can be applied to determine the holonomy of generalised Killing spinor covariant derivatives of the form $D= \

  15. Hidden symmetries and killing tensors on curved spaces

    SciTech Connect

    Ianus, S. [University of Bucharest, Department of Mathematics (Romania); Visinescu, M., E-mail: mvisin@theory.nipne.r [Institute for Physics and Nuclear Engineering, Department of Theoretical Physics (Romania); Vilcu, G. E. [Petroleum-Gas University of Ploiesti, Department of Mathematics and Computer Science (Romania)

    2010-11-15

    Higher-order symmetries corresponding to Killing tensors are investigated. The intimate relation between Killing-Yano tensors and nonstandard supersymmetries is pointed out. In the Dirac theory on curved spaces, Killing-Yano tensors generate Dirac-type operators involved in interesting algebraic structures as dynamical algebras or even infinite dimensional algebras or superalgebras. The general results are applied to space-times which appear in modern studies. One presents the infinite dimensional superalgebra of Dirac type operators on the 4-dimensional Euclidean Taub-NUT space that can be seen as a twisted loop algebra. The existence of the conformal Killing-Yano tensors is investigated for some spaces with mixed 3-Sasakian structures.

  16. Why Are Bad Products So Hard to Kill?

    E-print Network

    Simester, Duncan

    It is puzzling that firms often continue to invest in product development projects when they should know that demand will be low. We argue that bad products are hard to kill because firms face an inherent conflict when ...

  17. Surface structure influences contact killing of bacteria by copper

    PubMed Central

    Zeiger, Marco; Solioz, Marc; Edongué, Hervais; Arzt, Eduard; Schneider, Andreas S

    2014-01-01

    Copper kills bacteria rapidly by a mechanism that is not yet fully resolved. The antibacterial property of copper has raised interest in its use in hospitals, in place of plastic or stainless steel. On the latter surfaces, bacteria can survive for days or even weeks. Copper surfaces could thus provide a powerful accessory measure to curb nosocomial infections. We here investigated the effect of the copper surface structure on the efficiency of contact killing of Escherichia coli, an aspect which so far has received very little attention. It was shown that electroplated copper surfaces killed bacteria more rapidly than either polished copper or native rolled copper. The release of ionic copper was also more rapid from electroplated copper compared to the other materials. Scanning electron microscopy revealed that the bacteria nudged into the grooves between the copper grains of deposited copper. The findings suggest that, in terms of contact killing, more efficient copper surfaces can be engineered. PMID:24740976

  18. Drought and Beetle-Killed Piñon Pines in Arizona

    USGS Multimedia Gallery

    Drought and beetle-killed piñon pines in Walnut Canyon National Monument near Flagstaff, Arizona, amid some surviving trees. Forest drought stress is highly correlated with mortality from poor growth, bark beetle outbreaks, and high-severity fire....

  19. Drought and Beetle-Killed Piñon Pines in Arizona

    USGS Multimedia Gallery

    Drought and beetle-killed piñon pines in Walnut Canyon National Monument near Flagstaff, Arizona, amid a few surviving trees. Forest drought stress is strongly correlated with tree mortality from poor growth, bark beetle outbreaks, and high-severity fire....

  20. Inducible repair of alkylated DNA in microorganisms.

    PubMed

    Mielecki, Damian; Wrzesi?ski, Micha?; Grzesiuk, El?bieta

    2015-01-01

    Alkylating agents, which are widespread in the environment, also occur endogenously as primary and secondary metabolites. Such compounds have intrinsically extremely cytotoxic and frequently mutagenic effects, to which organisms have developed resistance by evolving multiple repair mechanisms to protect cellular DNA. One such defense against alkylation lesions is an inducible Adaptive (Ada) response. In Escherichia coli, the Ada response enhances cell resistance by the biosynthesis of four proteins: Ada, AlkA, AlkB, and AidB. The glycosidic bonds of the most cytotoxic lesion, N3-methyladenine (3meA), together with N3-methylguanine (3meG), O(2)-methylthymine (O(2)-meT), and O(2)-methylcytosine (O(2)-meC), are cleaved by AlkA DNA glycosylase. Lesions such as N1-methyladenine (1meA) and N3-methylcytosine (3meC) are removed from DNA and RNA by AlkB dioxygenase. Cytotoxic and mutagenic O(6)-methylguanine (O(6)meG) is repaired by Ada DNA methyltransferase, which transfers the methyl group onto its own cysteine residue from the methylated oxygen. We review (i) the individual Ada proteins Ada, AlkA, AlkB, AidB, and COG3826, with emphasis on the ubiquitous and versatile AlkB and its prokaryotic and eukaryotic homologs; (ii) the organization of the Ada regulon in several bacterial species; (iii) the mechanisms underlying activation of Ada transcription. In vivo and in silico analysis of various microorganisms shows the widespread existence and versatile organization of Ada regulon genes, including not only ada, alkA, alkB, and aidB but also COG3826, alkD, and other genes whose roles in repair of alkylated DNA remain to be elucidated. This review explores the comparative organization of Ada response and protein functions among bacterial species beyond the classical E. coli model. PMID:25795127

  1. Conformal Killing vector fields and a virial theorem

    E-print Network

    José F. Cariñena; Irina Gheorghiu; Eduardo Martínez; Patrícia Santos

    2014-10-08

    The virial theorem is formulated both intrinsically and in local coordinates for a Lagrangian system of mechanical type on a Riemann manifold. An import case studied in this paper is that of an affine virial function associated to a vector field on the configuration manifold. The special cases of a virial function associated to a Killing, a homothetic and a conformal Killing vector field are considered and the corresponding virial theorems are established for this type of functions.

  2. Approximate Killing vectors on S{sup 2}

    SciTech Connect

    Cook, Gregory B. [Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27006 (United States); Whiting, Bernard F. [Department of Physics, University of Florida, Gainesville, Florida 32611 (United States)

    2007-08-15

    We present a new method for computing the best approximation to a Killing vector on closed 2-surfaces that are topologically S{sup 2}. When solutions of Killing's equation do not exist, this method is shown to yield results superior to those produced by existing methods. In addition, this method appears to provide a new tool for studying the horizon geometry of distorted black holes.

  3. Flat deformation of a spacetime admitting two Killing fields

    E-print Network

    Josep Llosa; Jaume Carot

    2010-05-10

    It is shown that given an analytic Lorentzian metric on a 4-manifold, $g$, which admits two Killing vector fields, then it exists a local deformation law $\\eta = a g + b H$, where $H$ is a 2-dimensional projector, such that $\\eta$ is flat and admits the same Killing vectors. We also characterize the particular case when the projector $H$ coincides with the quotient metric. We apply some of our results to general stationary axisymmetric spacetimes

  4. Killing of bacteria with electric pulses of high field strength

    Microsoft Academic Search

    H. Hfilsheger; J. Potel; E.-G. Niemann

    1981-01-01

    Summary Bacteria of the typeE. coli K12 have been treated in experiments using high-voltage pulses of short time (µs) as a killing agent. The role of different experimental parameters has been studied: kind of electrolyte, concentration, length of pulses, field strength, pH and temperature. Electrolytes with bivalent cations were found to reduce the lethal action. The relative rate of killed

  5. Superoxide Dismutase Protects Escherichia coli against Killing by Human Serum

    Microsoft Academic Search

    D. C. Mcmanus; P. D. Josephy

    1995-01-01

    To assess the role of superoxide dismutase in protecting Escherichia coli from killing by human serum and neutrophils, we constructed isogenic, smooth-lipopolysaccharide K-12 strains, either sod wild-type, ?sodA, or ?sodA?sodB. The ?sodA?sodB strain was killed by serum much more readily than either the wild-type or ?sodA strain. After allowing for this serum sensitivity difference, the ?sodA?sodB strain also showed increased

  6. Conformal Killing vector fields and a virial theorem

    NASA Astrophysics Data System (ADS)

    Cariñena, José F.; Gheorghiu, Irina; Martínez, Eduardo; Santos, Patrícia

    2014-11-01

    The virial theorem is formulated both intrinsically and in local coordinates for a Lagrangian system of a mechanical type on a Riemann manifold. An important case studied in this paper is that of an affine virial function associated with a vector field on the configuration manifold. The special cases of a virial function associated with a Killing, a homothetic, and a conformal Killing vector field are considered and the corresponding virial theorems are established for these types of functions.

  7. Are Road Kills Valid Indicators of Armadillo Population Structure?

    Microsoft Academic Search

    J. LOUGHRY; COLLEEN M. McDONOUGH

    Wecollected 3 yr of data on road-killed nine-banded armadillos (Dasypus novemcinctus) to determine if these individuals were representative of the population as a whole. Comparisons between road kills and an adjacent live-caught population revealed no differences in sex ratios or the reproductive condition of adult females. However, there was a significant difference in the age structure of the two groups,

  8. On completeness of orbits of Killing vector fields

    E-print Network

    Piotr T. Chrusciel

    1993-04-21

    A Theorem is proved which reduces the problem of completeness of orbits of Killing vector fields in maximal globally hyperbolic, say vacuum, space--times to some properties of the orbits near the Cauchy surface. In particular it is shown that all Killing orbits are complete in maximal developements of asymptotically flat Cauchy data, or of Cauchy data prescribed on a compact manifold. This result gives a significant strengthening of the uniqueness theorems for black holes.

  9. 1. GENERAL VIEW OF HOG KILLING ROOM ON LEVEL 4; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW OF HOG KILLING ROOM ON LEVEL 4; LOOKING NORTHWEST; A PORTION OF THE SCALDING TANK IS VISIBLE AT EXTREME RIGHT, CENTER; CONCRETE PYLONS AT LOWER RIGHT SUPPORTED BY SCRAPING MACHINE; FINAL SCRAPING WAS DONE BY WORKERS STANDING ON ELEVATED PLATFORMS AT LEFT; BATHTUB-SHAPED CART NEAR CENTER OF PHOTO WAS USED TO TRANSPORT OFFAL TO RENDERING AREAS - Rath Packing Company, Hog Killing Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  10. Heat Melt Compaction as an Effective Treatment for Eliminating Microorganisms from Solid Waste

    NASA Technical Reports Server (NTRS)

    Hummerick, Mary P.; Strayer, Richard; McCoy, LaShelle; Richard, Jeffrey; Ruby, Anna; Wheeler, Raymond

    2012-01-01

    One of the technologies being tested at Ames Research Center as part of the logistics and repurposing project is heat melt compaction (HMC) of solid waste to reduce volume, remove water and render a biologically stable and safe product. Studies at Kennedy Space Center have focused on the efficacy of the heat melt compaction process for killing microorganisms in waste and specific compacter operation protocols, i.e., time and temperature, required to achieve a sterile, stable product. The work reported here includes a controlled study to examine the survival and potential re-growth of specific microorganisms over a 6-month period of storage after heating and compaction. Before heating and compaction, ersatz solid wastes were inoculated with Bacillus amyloliquefaciens and Rhodotorula mucilaginosa, previously isolated from recovered space shuttle mission food and packaging waste. Compacted HMC tiles were sampled for microbiological analysis at time points between 0 and 180 days of storage in a controlled environment chamber. In addition, biological indicator strips containing spores of Bacillus atrophaeus and Ceo bacillus stearothermophilus were imbedded in trash to assess the efficacy of the HMC process to achieve sterilization. Analysis of several tiles compacted at 180 C for times of 40 minutes to over 2 hours detected organisms in all tile samples with the exception of one exposed to 180 C for approximately 2 hours. Neither of the inoculated organisms was recovered, and the biological indicator strips were negative for growth in all tiles indicating at least local sterilization of tile areas. The findings suggest that minimum time/temperature combination is required for complete sterilization. Microbial analysis of tiles processed at lower temperatures from 130 C-150 C at varying times will be discussed, as well as analysis of the bacteria and fungi present on the compactor hardware as a result of exposure to the waste and the surrounding environment. The two organisms inoculated into the waste were among those isolated and identified from the HMC surfaces indicating the possibility of cross contamination.

  11. COMPOSTING: STABILIZATION, DEWATERING, VOLUME REDUCTION, AND PATHOGEN KILL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic composting is the biological oxidative decomposition of organic materials by successive communities of microorganisms under different temperature regimes which produces a humified end-product. Composting reduces moisture content of organic byproducts. Thermophilic temperatures attained dur...

  12. Extraluminal Colonic Carcinoma Invading into Kidney: A Case Report and Review of the Literature

    PubMed Central

    Nelson, J.; Rinard, K.; Haynes, A.; Filleur, S.; Nelius, T.

    2011-01-01

    Renal metastasis from primary colon cancer is very rare, comprising less than 3% of secondary renal neoplasms. There are just 11 cases reported in the medical literature of colonic adenocarcinoma metastatic to the kidney. Of these cases, none occurred via direct invasion. We report a unique case of a 51-year-old female with extraluminal colonic adenocarcinoma which directly invaded into the kidney. Additionally, we investigate the causal relationship between the site of invasion and a previous stab injury by reviewing the role of the peritoneum and Gerota's fascia in preventing the spread of metastatic cancer into the perirenal space. Due to the rarity of this event, we present this case including a review of the existing literature relative to the diagnosis and treatment. PMID:22084803

  13. Transferring automation for large-scale development and production of Invader SNP assays

    NASA Astrophysics Data System (ADS)

    Neri, Bruce P.; Ganske, R.; Isaczyszyn, W.; Beaty, Edward L.

    2000-03-01

    The Human Genome Project has led to the discovery of hundreds of thousands of single nucleotide polymorphisms (SNPs). SNPs can act as genetic markers to create high- density maps of the human genome for large-scale genetic analysis for evaluating links between genetic mutations and human diseases and for performing association studies. To create those maps, assays capable of detecting many different SNPs must be developed rapidly, as additional SNPs are discovered. When both the design of and the technology used in the assays can be partially or fully automated, the development process and the time to results can be accomplished quickly and efficiently. InvaderTM technology offers a highly sensitive signal amplification system that detects and quantifies mutations and SNPs from unamplified human genomic DNA in two sequential steps.

  14. Successful resection of thymoma directly invading the right atrium under cardiopulmonary bypass.

    PubMed

    De Giacomo, Tiziano; Patella, Miriam; Mazzesi, Giuseppe; Venuta, Federico

    2015-08-01

    We present the case of an invasive thymoma with severe compression of the right atrium, and infiltration of the atrial wall, causing a superior vena cava (SVC) syndrome. The tumour was resected under cardiopulmonary bypass en bloc with the atrial wall. A bovine pericardial patch was used for atrial reconstruction. We obtained a complete resection of the tumour and regression of symptoms, and, after 1 year of the follow-up, no signs of recurrence are evident. To our knowledge, this is the first case of thymoma directly invading the right atrium, without involvement of the SVC. In this setting, the aggressive surgical approach led to an immediate resolution of the symptoms and contributed to prolonged long-term survival. PMID:25293404

  15. Assessment of the Ozone-Mediated Killing of Bacteria in Infected Dentine Associated with Non-Cavitated Occlusal Carious Lesions

    PubMed Central

    Baysan, A.; Beighton, D.

    2007-01-01

    The ability of ozone to kill micro-organisms associated with non-cavitated occlusal caries was investigated. The occlusal surfaces were treated with ozone (n = 53) or air (n = 49) for 40 s, and the underlying infected dentine was exposed. There was no significant difference between the number of bacteria recovered from the ozone-treated and the control sites (p > 0.1). Treatment of the exposed dentine with ozone resulted in a just significant (p = 0.044) reduction in bacterial counts. Ozone treatment of non-cavitated occlusal lesions for 40 s failed to significantly reduce the numbers of viable bacteria in infected dentine beneath the demineralized enamel. PMID:17713332

  16. Oceanographic Conditions Limit the Spread of a Marine Invader along Southern African Shores

    PubMed Central

    Nicastro, Katy R.; Zardi, Gerardo I.; McQuaid, Christopher D.; Serrão, Ester A.

    2015-01-01

    Invasive species can affect the function and structure of natural ecological communities, hence understanding and predicting their potential for spreading is a major ecological challenge. Once established in a new region, the spread of invasive species is largely controlled by their dispersal capacity, local environmental conditions and species interactions. The mussel Mytilus galloprovincialis is native to the Mediterranean and is the most successful marine invader in southern Africa. Its distribution there has expanded rapidly and extensively since the 1970s, however, over the last decade its spread has ceased. In this study, we coupled broad scale field surveys, Ecological Niche Modelling (ENM) and Lagrangian Particle Simulations (LPS) to assess the current invaded distribution of M. galloprovincialis in southern Africa and to evaluate what prevents further spread of this species. Results showed that all environmentally suitable habitats in southern Africa have been occupied by the species. This includes rocky shores between Rocky Point in Namibia and East London in South Africa (approx. 2800 km) and these limits coincide with the steep transitions between cool-temperate and subtropical-warmer climates, on both west and southeast African coasts. On the west coast, simulations of drifting larvae almost entirely followed the northward and offshore direction of the Benguela current, creating a clear dispersal barrier by advecting larvae away from the coast. On the southeast coast, nearshore currents give larvae the potential to move eastwards, against the prevalent Agulhas current and beyond the present distributional limit, however environmental conditions prevent the establishment of the species. The transition between the cooler and warmer water regimes is therefore the main factor limiting the northern spread on the southeast coast; however, biotic interactions with native fauna may also play an important role. PMID:26114766

  17. A generic risk-based surveying method for invading plant pathogens.

    PubMed

    Parnell, S; Gottwald, T R; Riley, T; van den Bosch, F

    2014-06-01

    Invasive plant pathogens are increasing with international trade and travel, with damaging environmental and economic consequences. Recent examples include tree diseases such as sudden oak death in the Western United States and ash dieback in Europe. To control an invading pathogen it is crucial that newly infected sites are quickly detected so that measures can be implemented to control the epidemic. However, since sampling resources are often limited, not all locations can be inspected and locations must be prioritized for surveying. Existing approaches to achieve this are often species specific and rely on detailed data collection and parameterization, which is difficult, especially when new arrivals are unanticipated. Consequently regulatory sampling responses are often ad hoc and developed without due consideration of epidemiology, leading to the suboptimal deployment of expensive sampling resources. We introduce a flexible risk-based sampling method that is pathogen generic and enables available information to be utilized to develop epidemiologically informed sampling programs for virtually any biologically relevant plant pathogen. By targeting risk we aim to inform sampling schemes that identify high-impact locations that can be subsequently treated in order to reduce inoculum in the landscape. This "damage limitation" is often the initial management objective following the first discovery of a new invader. Risk at each location is determined by the product of the basic reproductive number (R0), as a measure of local epidemic size, and the probability of infection. We illustrate how the risk estimates can be used to prioritize a survey by weighting a random sample so that the highest-risk locations have the highest probability of selection. We demonstrate and test the method using a high-quality spatially and temporally resolved data set on Huanglongbing disease (HLB) in Florida, USA. We show that even when available epidemiological information is relatively minimal, the method has strong predictive value and can result in highly effective targeted surveying plans. PMID:24988776

  18. Differences in ecological structure, function, and native species abundance between native and invaded Hawaiian streams.

    PubMed

    Holitzki, Tara M; MacKenzie, Richard A; Wiegner, Tracy N; McDermid, Karla J

    2013-09-01

    Poeciliids, one of the most invasive species worldwide, are found on almost every continent and have been identified as an "invasive species of concern" in the United States, New Zealand, and Australia. Despite their global prevalence, few studies have quantified their impacts on tropical stream ecosystem structure, function, and biodiversity. Utilizing Hawaiian streams as model ecosystems, we documented how ecological structure, function, and native species abundance differed between poeciliid-free and poeciliid-invaded tropical streams. Stream nutrient yields, benthic biofilm biomass, densities of macroinvertebrates and fish, and community structures of benthic algae, macroinvertebrates, and fish were compared between streams with and without established poeciliid populations on the island of Hawai'i, Hawaii, USA. Sum nitrate (sigmaNO3(-) = NO3(-) + NO2(-)), total nitrogen, and total organic carbon yields were eight times, six times, and five times higher, respectively, in poeciliid streams than in poeciliid-free streams. Benthic biofilm ash-free dry mass was 1.5x higher in poeciliid streams than in poeciliid-free streams. Percentage contributions of chironomids and hydroptilid caddisflies to macroinvertebrate densities were lower in poeciliid streams compared to poeciliid-free streams, while percentage contributions of Cheumatopsyche analis caddisflies, Dugesia sp. flatworms, and oligochaetes were higher. Additionally, mean densities of native gobies were two times lower in poeciliid streams than in poeciliid-free ones, with poeciliid densities being approximately eight times higher than native fish densities. Our results, coupled with the wide distribution of invasive poeciliids across Hawaii and elsewhere in the tropics, suggest that poeciliids may negatively impact the ecosystem structure, function, and native species abundance of tropical streams they invade. This underscores the need for increased public awareness to prevent future introductions and for developing and implementing effective eradication and restoration strategies. PMID:24147409

  19. Technologies for Beneficial Microorganisms Inocula Used as Biofertilizers

    PubMed Central

    Malusá, E.; Sas-Paszt, L.; Ciesielska, J.

    2012-01-01

    The increasing need for environmentaly friendly agricultural practices is driving the use of fertilizers based on beneficial microorganisms. The latter belong to a wide array of genera, classes, and phyla, ranging from bacteria to yeasts and fungi, which can support plant nutrition with different mechanisms. Moreover, studies on the interactions between plant, soil, and the different microorganisms are shedding light on their interrelationships thus providing new possible ways to exploit them for agricultural purposes. However, even though the inoculation of plants with these microorganisms is a well-known practice, the formulation of inocula with a reliable and consistent effect under field conditions is still a bottleneck for their wider use. The choice of the technology for inocula production and of the carrier for the formulation is key to their successful application. This paper focuses on how inoculation issues can be approached to improve the performance of beneficial microorganisms used as a tool for enhancing plant growth and yield. PMID:22547984

  20. APPROACHES FOR DEFINING TREATABILITY AND DISINFECTION OF CCL MICROORGANISMS

    EPA Science Inventory

    The product evaluates three disinfectant methods , chlorine, Ultraviolet light and ozone in their effectiveness against all the listed CCL microorganisms (bacteria, viruses and protozoa). Surrogates for nonculturable viruses were included. The susceptibility evaluation data of CP...

  1. Effects of heat-activated persulfate oxidation on soil microorganisms.

    PubMed

    Tsitonaki, Aikaterini; Smets, Barth F; Bjerg, Poul L

    2008-02-01

    The effects of heat-activated persulfate on indigenous microorganisms and microcosms augmented with Pseudomonas putida KT2440 were studied in laboratory batch reactors with aquifer material. Microscopic enumeration was used to measure the changes in cell density, and acetate consumption was used to evaluate metabolic activity after exposure to activated persulfate. The cell enumerations showed that persulfate concentrations up to 10 g/L did not affect the indigenous microorganisms but were detrimental to P. putida survival. Acetate consumption was inhibited at the highest persulfate dose (10 g/L). The results emphasize the necessity of using multiple toxicity assays and indigenous cultures in order to realistically assess the potential effects of in situ chemical oxidation on soil microorganisms. A comparison to other studies suggests that the effects of activated persulfate on soil microorganisms are less damaging than those of Fenton's reagent and hydrogen peroxide. PMID:17942135

  2. Multiorganismal insects: diversity and function of resident microorganisms.

    PubMed

    Douglas, Angela E

    2015-01-01

    All insects are colonized by microorganisms on the insect exoskeleton, in the gut and hemocoel, and within insect cells. The insect microbiota is generally different from microorganisms in the external environment, including ingested food. Specifically, certain microbial taxa are favored by the conditions and resources in the insect habitat, by their tolerance of insect immunity, and by specific mechanisms for their transmission. The resident microorganisms can promote insect fitness by contributing to nutrition, especially by providing essential amino acids, B vitamins, and, for fungal partners, sterols. Some microorganisms protect their insect hosts against pathogens, parasitoids, and other parasites by synthesizing specific toxins or modifying the insect immune system. Priorities for future research include elucidation of microbial contributions to detoxification, especially of plant allelochemicals in phytophagous insects, and resistance to pathogens; as well as their role in among-insect communication; and the potential value of manipulation of the microbiota to control insect pests. PMID:25341109

  3. Selective microorganism concentration using a dielectrophoresis-based microfabricated device

    E-print Network

    Pucha?a, Katarzyna Anna

    2007-01-01

    Detection of pathogenic microorganisms is a significant challenge in medicine, environmental protection and biological threat safety because samples are often contaminated. This work presents a method of separating bacterial ...

  4. EVALUATING THE MAINTENANCE AND EFFECTS OF GENETICALLY ENGINEERED MICROORGANISMS

    EPA Science Inventory

    Concepts and methods were identified for their utility in evaluating the persistence and potential perturbations of genetically engineered microorganisms in the environment. Novel uses of DNA reassociation kinetics and gene probe technologies, in conjunction with conventional bac...

  5. CONTROL OF MICROORGANISMS OF PUBLIC HEALTH CONCERN IN WATER

    EPA Science Inventory

    Microorganisms of public health concern in water can be controlled by treatment process technology currently available. Where outbreaks have occurred, the cause has been a demonstrated failure in wastewater or water supply treatment operation or distribution protection. While nat...

  6. PHYSICAL AND CHEMICAL CONTROL OF RELEASED MICROORGANISMS AT FIELD SITES

    EPA Science Inventory

    An important consideration in the environmental release of a genetically engineered microorganism (GEM) is the capability for reduction or elimination of GEM populations once their function is completed or if adverse environmental effects are observed. In this study the decontami...

  7. Engineering of microorganisms towards recovery of rare metal ions

    Microsoft Academic Search

    Kouichi Kuroda; Mitsuyoshi Ueda

    2010-01-01

    The bioadsorption of metal ions using microorganisms is an attractive technology for the recovery of rare metal ions as well\\u000a as removal of toxic heavy metal ions from aqueous solution. In initial attempts, microorganisms with the ability to accumulate\\u000a metal ions were isolated from nature and intracellular accumulation was enhanced by the overproduction of metal-binding proteins\\u000a in the cytoplasm. As

  8. Inulinase-expressing microorganisms and applications of inulinases

    Microsoft Academic Search

    Zhenming Chi; Zhe Chi; Tong Zhang; Guanglei Liu; Lixi Yue

    2009-01-01

    In this review article, inulinase-expressing microorganisms and its potential applications in transformation of inulin into\\u000a very-high-fructose syrup, bioethanol, and inulooligosaccharides are overviewed. In the past 10 years, many new inulinase producers\\u000a have been obtained and many genes encoding inulinases from different microorganisms have been cloned and characterized. Some\\u000a novel processes for exoinulinase overproduction have been developed for bioethanol production and ultra-high-fructose

  9. Marine Microorganisms: perspectives for getting involved in cellulosic ethanol.

    PubMed

    Intriago, Pablo

    2012-01-01

    The production of ethanol has been considered as an alternative to replace part of the petroleum derivate. Brazil and the US are the leading producers, but more environmentally friendly alternatives are needed. Lignocellulose has an enormous potential but technology has to be still improve in order to economically produce ethanol. The present paper reviews the potential and problems of this technology and proposes the study of a group of microorganisms with the largest genetic pool, marine microorganism. PMID:22931793

  10. Biodiversity of microorganisms that degrade bacterial and synthetic polyesters

    Microsoft Academic Search

    J Mergaert; J Swings

    1996-01-01

    The biodiversity and occurrence in nature of bioplastic-degrading microorganisms are exemplified by the identification of 695 strains, isolated from different environments, such as soils, composts, natural waters, and sludge, that are able to degrade the bacterial polyester poly(3-hydroxybutyrate)in vitro. These microorganisms belong to at least 57 different taxa, including Gram-negative and Gram-positive bacteria, streptomycetes, and moulds. The literature on the

  11. Studies on the activities of rumen microorganisms in vitro 

    E-print Network

    Johnson, Carl Edward

    1957-01-01

    EXTRACTS AND SUCROSE SOLUTIONS TO INHIBIT CELLULOSE DIGESTION BI RUMEN MICROORGANISMS IN VITRO PART III l. SLVFRAL TYPES OF FISTULA PLUGS USED fN RUMEN STUDIES . ~ ~ 47 2. A NEW TYPE OF BJEUFATIC FISTULA PLUG 49 DETAILS OF CONSTRUCTION OF THE PNEUMATIC... FISTULA PLUG . . 50 PART I EFFECTS OF MESQUITE BEAN EXTRACTS ON THE DIGESTION OF CELLULOSE BY RUMEN MICROORGANISMS INTRODUCTION Mesquite beans have been used as feed for oattle sinoe the extensive invasion by the mesquite tree (PORN~, )~i...

  12. Method for treating wastewater using microorganisms and vascular aquatic plants

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C. (inventor)

    1983-01-01

    A method for treating wastewater compresses subjecting the wastewater to an anaerobic setting step for at least 6 hours and passing the liquid effluent from the anaerobic settling step through a filter cell in an upflow manner. There the effluent is subjected first to the action of anaerobic and facultative microorganisms, and then to the action of aerobic microorganisms and the roots of at least one vascular aquatic plant.

  13. THE PRECISE TAIL BEHAVIOR OF THE TOTAL PROGENY OF A KILLED BRANCHING RANDOM WALK

    E-print Network

    Paris-Sud XI, Université de

    THE PRECISE TAIL BEHAVIOR OF THE TOTAL PROGENY OF A KILLED BRANCHING RANDOM WALK ELIE AIDEKON line with a killing barrier at zero: starting from a nonnegative point, particles reproduce and move independently, but are killed when they touch the negative half-line. The population of the killed branching

  14. July/August 2012 Newsletter Subscriptions Bee-Kill Survey USDA APHIS Survey Canadian Nosema Studies

    E-print Network

    Ferrara, Katherine W.

    ________________________________________________________________________________ Newsletter Subscriptions Bee-Kill Survey USDA APHIS Survey Canadian Nosema Studies, but instead of Subscribe, you use the Unsubscribe. Bee-Kill Survey on Acute Bee Kills Limited response to their formal bee kill report solicitation prompted the US EPA Pesticide Program Dialog Committee (PPDC

  15. Elevated CO 2 differentially alters belowground plant and soil microbial community structure in reed canary grass-invaded experimental wetlands

    Microsoft Academic Search

    Jenny Kao-Kniffin; Teri C. Balser

    2007-01-01

    Several recent studies have indicated that an enriched atmosphere of carbon dioxide (CO2) could exacerbate the intensity of plant invasions within natural ecosystems, but little is known of how rising CO2 impacts the belowground characteristics of these invaded systems. In this study, we examined the effects of elevated CO2 and nitrogen (N) inputs on plant and soil microbial community characteristics

  16. Reshaping the Ecology of Invading Populations of Hemlock Woolly Adelgid, Adelges tsugae (Homoptera: Adelgidae), in Eastern North America

    Microsoft Academic Search

    Mark S. McClure; Carole A. S.-J. Cheah

    1999-01-01

    Hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae), is native to Japan where it is an innocuous inhabitant of Tsuga diversifolia Masters and T. sieboldii Carriere throughout their natural growing areas. Native adelgid populations are regulated by host resistance and natural enemies, in particular the oribatid mite, Diapterobates humeralis (Hermann) and the coccinellid beetle, Pseudoscymnus tsugae Sasaji and McClure. Invading

  17. Summary. The Argentine ant, Linepithema humile, has invaded many areas of the world, displacing native ants. Its

    E-print Network

    Gordon, Deborah

    Summary. The Argentine ant, Linepithema humile, has invaded many areas of the world, displacing native ants. Its behavior may contribute to its competitive success. Staged and natural encounters were observed at food resources in the field, between Argentine ants and eight ant species native to northern

  18. An experimental investigation of the competitive displacement of a native gecko by an invading gecko: no role for parasites

    Microsoft Academic Search

    Kathryn A. Hanley; Kenneth Petren; Ted J. Case

    1998-01-01

    On islands across the Pacific the invasion of the gecko Hemidactylusfrenatus has caused a decline in the abundance of a resident gecko, Lepidodactyluslugubris. In a previous study we demonstrated that the prevalence of the cestode Cylindrotaenia sp. is higher in the resident gecko on islands where it is sympatric with the invader than on islands where it occurs alone.\\u000a In

  19. Impact of Exotic Invertebrate Invaders on Food Web Structure and Function in the Great Lakes: a Network Analysis Approach

    E-print Network

    Impact of Exotic Invertebrate Invaders on Food Web Structure and Function in the Great Lakes a second wave of species invasions dominated by exotic invertebrates- Zebra mussels (Dreissena polymorpha invasions (e.g., sea Lamprey and Alewife), these invertebrates inserted themselves in the lower trophic

  20. Assessing invader roles within changing ecosystems: historical and experimental perspectives on an exotic mussel in an urbanized lagoon

    Microsoft Academic Search

    Jeffrey A. Crooks

    2001-01-01

    It is often difficult to accurately assess the long-term effects of invaders because of a lack of data and the changing nature of ecosystems. However, available historical information can be used to make comparisons with current conditions and generate hypotheses that can be tested experimentally. This approach was used to examine changes in the bivalve community of Mission Bay, San

  1. Can imazapic and seeding be applied simultaneously to rehabilitate medusahead-invaded rangeland? Single vs. multiple entry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has recently been proposed that reducing the cost of rehabilitating medusahead (Taeniatherum caput-medusae (L.) Nevski)-invaded rangelands may be attained by seeding desired vegetation with a concurrent application of the pre-emergent herbicide (imazapic). However, the efficacy of this “single e...

  2. Population responses of hymenopteran parasitoids to the emerald ash borer (Coleoptera: Buprestidae) in recently invaded areas in Michigan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Populations of hymenopteran parasitoids associated with immature stages of the invasive emerald ash borer (EAB) Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) were surveyed in 2009 and 2010 in the recently invaded areas in Michigan, where the two introduced EAB larval parasitoids, Tetrastic...

  3. Naturalized plants have smaller genomes than their non-invading relatives: a flow cytometric analysis of the Czech alien flora

    E-print Network

    Kratochvíl, Lukas

    analysis of the Czech alien flora Naturalizované rostliny mají mensí genom nez neinvadující druhy than their non-invading relatives: a flow cytometric analysis of the Czech alien flora. ­ Preslia 82 in 93 alien species naturalized in the Czech Republic, belonging to 32 families, by using flow cytometry

  4. Involvement of lectin pathway activation in the complement killing of Giardia intestinalis.

    PubMed

    Evans-Osses, Ingrid; Ansa-Addo, Ephraim A; Inal, Jameel M; Ramirez, Marcel I

    2010-05-01

    Giardia intestinalis (syn. G. lamblia, G. duodenalis) is a flagellated unicellular eukaryotic microorganism that commonly causes diarrheal disease throughout the world. In humans, the clinical effects of Giardia infection range from the asymptomatic carrier state to a severe malabsorption syndrome possibly due to different virulence of the Giardia strain, the number of cysts ingested, the age of the host, and the state of the host immune system at the time of infection. The question about how G. intestinalis is controlled by the organism remains unanswered. Here, we investigated the role of the complement system and in particular, the lectin pathway during Giardia infections. We present the first evidence that G. intestinalis activate the complement lectin pathway and in doing so participate in eradication of the parasite. We detected rapid binding of mannan-binding lectin, H-ficolin and L-ficolin to the surface of G. intestinalis trophozoites and normal human serum depleted of these molecules failed to kill the parasites. Our finding provides insight into the role of lectin pathway in the control of G. intestinalis and about the nature of surface components of parasite. PMID:20382117

  5. Survival of microorganisms under the extreme conditions of the Atacama Desert.

    PubMed

    Dose, K; Bieger-Dose, A; Ernst, B; Feister, U; Gómez-Silva, B; Klein, A; Risi, S; Stridde, C

    2001-06-01

    Spores of Bacillus subtilis, conidia of Aspergillus niger, versicolor and ochraceus and cells of Deinococcus radiodurans have been exposed in the dark at two locations (at about 23 degrees S and 24 degrees S) in the Atacama Desert for up to 15 months. B. subtilis spores (survival approximately 15%) and A. niger conidia (survival approximately 30%) outlived the other species. The survival of the conidia and spores species was only slightly poorer than that of the corresponding laboratory controls. However, the Deinococcus radiodurans cells did not survive the desert exposure, because they are readily inactivated at relative humidities between 40 and 80% which typically occur during desert nights. Cellular monolayers of the dry spores and conidia have in addition been exposed to the full sun light for up to several hours. The solar fluences causing 63% loss in viability (F37-values) have been determined. These F37-values are compared with those determined at other global locations such as Punta Arenas (53 degrees S), Key Largo (25 degrees N) or Mainz (50 degrees N) during the same season. The solar UVB radiation kills even the most resistant microorganisms within a few hours due to DNA damages. The data are also discussed with respect to possible similarities between the climatic conditions of the recent Atacama Desert and the deserts of early Mars. PMID:11434107

  6. Immunology 101 Killing in acute viral infections Killing in chronic viral infections Appendix I Appendix II Extra Mathematical models of CD8 T cell responses

    E-print Network

    Haase, Markus

    Immunology 101 Killing in acute viral infections Killing in chronic viral infections Appendix I in vivo Vitaly V. Ganusov Los Alamos National Laboratory Los Alamos, NM, USA 1 / 55 #12;Immunology 101 1 Immunology 101 Immune system 2 Killing in acute viral infections Experimental details Model 3

  7. Stoichiometric Constraints Do Not Limit Successful Invaders: Zebra Mussels in Swedish Lakes

    PubMed Central

    Naddafi, Rahmat; Eklöv, Peter; Pettersson, Kurt

    2009-01-01

    Background Elemental imbalances of carbon (C): nitrogen (N): phosphorus (P) ratios in food resources can constrain the growth of grazers owning to tight coupling between growth rate, RNA allocation and biomass P content in animals. Testing for stoichiometric constraints among invasive species is a novel challenge in invasion ecology to unravel how a successful invader tackles ecological barriers in novel ecosystems. Methodology/Principal Findings We examined the C?P and N?P ratios and the condition factor of a successful invader in lakes, the zebra mussel (Dreissena polymorpha), collected from two Swedish lakes. Concurrently, we analyzed the elemental composition of the food (seston) and tissue of the mussels in which nutrient composition of food and mussels varied over time. Zebra mussel condition factor was weakly related to the their own tissue N?P and C?P ratios, although the relation with the later ratio was not significant. Smaller mussels had relatively lower tissue N?P ratio and higher condition factor. There was no difference in C?P and N?P ratios between seston and mussels' tissues. Our results indicated that the variation in nutrient stoichiometry of zebra mussels can be explained by food quality and quantity. Conclusions/Significance Our study suggests that fitness of invasive zebra mussels is not constrained by nutrient stoichiometry which is likely to be important for their proliferation in novel ecosystems. The lack of imbalance in C?P and N?P ratios between seston and mussels along with high tissue C?P ratio of the mussel allow them to tolerate potential P limitation and maintain high growth rate. Moreover, zebra mussels are able to change their tissue C?P and N?P ratios in response to the variation in elemental composition of their food. This can also help them to bypass potential nutrient stoichiometric constraints. Our finding is an important step towards understanding the mechanisms contributing to the success of exotic species from stoichiometric principles. PMID:19401773

  8. Hepatocellular Carcinoma Invading the Main Portal Vein: Treatment with Transcatheter Arterial Chemoembolization and Portal Vein Stenting

    SciTech Connect

    Zhang Xuebin, E-mail: zhangxuebinwqy@163.com; Wang Jianhua, E-mail: wang.jianhua@zs-hospital.sh.cn; Yan Zhiping, E-mail: yan.zhiping@zs-hospital.sh.cn; Qian Sheng, E-mail: qian.sheng@zs-hospital.sh.cn; Liu Rong, E-mail: liu.rong@zs-hospital.sh.c [Fudan University, Department of Radiology, Zhong Shan Hospital (China)

    2009-01-15

    To retrospectively analyze the therapeutic results of percutaneous transhepatic portal vein stenting (PTPVS) and transcatheter arterial chemoembolization (TACE) treatment in 58 patients with hepatocellular carcinoma (HCC) invading the main portal vein (MPV). A total of 58 procedures of PTPVS were performed, immediately after which TACE was undertaken to control HCC. The clinical effects, complications, digital subtraction angiographic appearance, stent patency rates, cumulative survival rates, and predictive factors for survival were evaluated. The Kaplan-Meyer method and the log rank test were used for survival analysis. Multivariable analysis was also conducted by the Cox proportional hazard model. No patient died during stent placement or within the first 24 h. No severe procedure-related complications were observed. After stent placement, the mean {+-} standard deviation portal venous pressure levels decreased from 41.43 {+-} 8.56 cmH{sub 2}O to 37.19 {+-} 7.89 cmH{sub 2}O (p < 0.01). At the time of analysis, 9 of the 58 patients survived. The 60-, 180-, 360-, and 720-day cumulative patency rates were 98.1%, 71.0%, 52.6%, and 42.1%, respectively, with a mean patency time of 552.9 {+-} 88.2 days and a median patency time of 639.00 {+-} 310.00 (95% confidence interval [95% CI], 31.40-1246.60) days. The 60-, 180-, 360-, and 720-day cumulative survival rates for the total study population were 74.1%, 27.1%, 17.2%, and 13.8%, respectively, with a median survival time of 113 {+-} 27.29 (95% CI, 59.51-166.49) days. In the univariate analysis, the following six variables were significantly associated with the prognosis: (1) HCC type; (2) Child-Pugh grade; (3) MPV stenosis/occlusion; (4) arteriovenous shunt; (5) iodized oil deposition; and (6) number of TACE procedure. In addition, having diffuse-type HCC and Child-Pugh grade B disease were each independent factors associated with decreased survival time in the multivariate analysis. PTPVS-TACE is feasible and may be useful to control HCC invading the MPV.

  9. Hepatocellular carcinoma invading the main portal vein: treatment with transcatheter arterial chemoembolization and portal vein stenting.

    PubMed

    Zhang, Xue-Bin; Wang, Jian-Hua; Yan, Zhi-Ping; Qian, Sheng; Liu, Rong

    2009-01-01

    To retrospectively analyze the therapeutic results of percutaneous transhepatic portal vein stenting (PTPVS) and transcatheter arterial chemoembolization (TACE) treatment in 58 patients with hepatocellular carcinoma (HCC) invading the main portal vein (MPV). A total of 58 procedures of PTPVS were performed, immediately after which TACE was undertaken to control HCC. The clinical effects, complications, digital subtraction angiographic appearance, stent patency rates, cumulative survival rates, and predictive factors for survival were evaluated. The Kaplan-Meyer method and the log rank test were used for survival analysis. Multivariable analysis was also conducted by the Cox proportional hazard model. No patient died during stent placement or within the first 24 h. No severe procedure-related complications were observed. After stent placement, the mean +/- standard deviation portal venous pressure levels decreased from 41.43 +/- 8.56 cmH(2)O to 37.19 +/- 7.89 cmH(2)O (p < 0.01). At the time of analysis, 9 of the 58 patients survived. The 60-, 180-, 360-, and 720-day cumulative patency rates were 98.1%, 71.0%, 52.6%, and 42.1%, respectively, with a mean patency time of 552.9 +/- 88.2 days and a median patency time of 639.00 +/- 310.00 (95% confidence interval [95% CI], 31.40-1246.60) days. The 60-, 180-, 360-, and 720-day cumulative survival rates for the total study population were 74.1%, 27.1%, 17.2%, and 13.8%, respectively, with a median survival time of 113 +/- 27.29 (95% CI, 59.51-166.49) days. In the univariate analysis, the following six variables were significantly associated with the prognosis: (1) HCC type; (2) Child-Pugh grade; (3) MPV stenosis/occlusion; (4) arteriovenous shunt; (5) iodized oil deposition; and (6) number of TACE procedure. In addition, having diffuse-type HCC and Child-Pugh grade B disease were each independent factors associated with decreased survival time in the multivariate analysis. PTPVS-TACE is feasible and may be useful to control HCC invading the MPV. PMID:18931871

  10. Killing-Yano equations and G-structures

    E-print Network

    G. Papadopoulos

    2008-04-28

    We solve the Killing-Yano equation on manifolds with a $G$-structure for $G=SO(n), U(n), SU(n), Sp(n)\\cdot Sp(1), Sp(n), G_2$ and $Spin(7)$. Solutions include nearly-K\\"ahler, weak holonomy $G_2$, balanced SU(n) and holonomy $G$ manifolds. As an application, we find that particle probes on $AdS_4\\times X$ compactifications of type IIA and 11-dimensional supergravity admit a ${\\cal W}$-type of symmetry generated by the fundamental forms. We also explore the ${\\cal W}$-symmetries of string and particle actions in heterotic and common sector supersymmetric backgrounds. In the heterotic case, the generators of the ${\\cal W}$-symmetries completely characterize the solutions of the gravitino Killing spinor equation, and the structure constants of the ${\\cal W}$-symmetry algebra depend on the solution of the dilatino Killing spinor equation.

  11. Killing and Noether Symmetries of Plane Symmetric Spacetime

    E-print Network

    Shamir, M Farasat; Bhatti, Akhlaq Ahmad

    2015-01-01

    This paper is devoted to investigate the Killing and Noether symmetries of static plane symmetric spacetime. For this purpose, five different cases have been discussed. The Killing and Noether symmetries of Minkwoski spacetime in cartesian coordinates are calculated as a special case and it is found that Lie algebra of the Lagrangian is 10 and 17 dimensional respectively. The symmetries of Taub's universe, anti-deSitter universe, self similar solutions of in?finite kind for parallel perfect fluid case and self similar solutions of infinite kind for parallel dust case are also explored. In all the cases, the Noether generators are calculated in the presence of gauge term. All these examples justify the conjecture that Killing symmetries form a subalgebra of Noether symmetries [1].

  12. Killing and Noether Symmetries of Plane Symmetric Spacetime

    E-print Network

    M. Farasat Shamir; Adil Jhangeer; Akhlaq Ahmad Bhatti

    2015-06-26

    This paper is devoted to investigate the Killing and Noether symmetries of static plane symmetric spacetime. For this purpose, five different cases have been discussed. The Killing and Noether symmetries of Minkwoski spacetime in cartesian coordinates are calculated as a special case and it is found that Lie algebra of the Lagrangian is 10 and 17 dimensional respectively. The symmetries of Taub's universe, anti-deSitter universe, self similar solutions of in?finite kind for parallel perfect fluid case and self similar solutions of infinite kind for parallel dust case are also explored. In all the cases, the Noether generators are calculated in the presence of gauge term. All these examples justify the conjecture that Killing symmetries form a subalgebra of Noether symmetries [1].

  13. Reactive oxygen species-mediated bacterial killing by B lymphocytes.

    PubMed

    Kovács, István; Horváth, Magdolna; Lányi, Árpád; Pethe?, Gábor L; Geiszt, Miklós

    2015-06-01

    Regulated production of ROS is mainly attributed to Nox family enzymes. In neutrophil granulocytes and macrophages, Nox2 has a crucial role in bacterial killing, and the absence of phagocytic ROS production leads to the development of CGD. Expression of Nox2 was also described in B lymphocytes, where the role of the enzyme is still poorly understood. Here, we show that peritoneal B cells, which were shown recently to possess phagocytic activity, have a high capacity to produce ROS in a Nox2-dependent manner. In phagocytosing B cells, intense intraphagosomal ROS production is detected. Finally, by studying 2 animal models of CGD, we demonstrate that phagocyte oxidase-deficient B cells have a reduced capacity to kill bacteria. Our observations extend the number of immune cell types that produce ROS to kill pathogens. PMID:25821233

  14. Almost-Killing conserved currents: A general mass function

    NASA Astrophysics Data System (ADS)

    Ruiz, Milton; Palenzuela, Carlos; Bona, Carles

    2014-01-01

    A new class of conserved currents, describing nongravitational energy-momentum density, is presented. The proposed currents do not require the existence of a (timelike) Killing vector, and are not restricted to spherically symmetric spacetimes (or similar ones, in which the Kodama vector can be defined). They are based instead on almost-Killing vectors, which could in principle be defined on generic spacetimes. We provide local arguments, based on energy density profiles in highly simplified (stationary, rigidly rotating) star models, which confirm the physical interest of these almost-Killing currents. A mass function is defined in this way for the spherical case, qualitatively different from the Hernández-Misner mass function. An elliptic equation determining the new mass function is derived for the Tolman-Bondi spherically symmetric dust metrics, including a simple solution for the Oppenheimer-Snyder collapse. The equations for the nonsymmetric case are shown to be of a mixed elliptic-hyperbolic nature.

  15. Killing and Noether Symmetries of Plane Symmetric Spacetime

    NASA Astrophysics Data System (ADS)

    Shamir, M. Farasat; Jhangeer, Adil; Bhatti, Akhlaq Ahmad

    2013-09-01

    This paper is devoted to investigate the Killing and Noether symmetries of static plane symmetric spacetime. For this purpose, five different cases have been discussed. The Killing and Noether symmetries of Minkowski spacetime in cartesian coordinates are calculated as a special case and it is found that Lie algebra of the Lagrangian is 10 and 17 dimensional respectively. The symmetries of Taub's universe, anti-deSitter universe, self similar solutions of infinite kind for parallel perfect fluid case and self similar solutions of infinite kind for parallel dust case are also explored. In all the cases, the Noether generators are calculated in the presence of gauge term. All these examples justify the conjecture that Killing symmetries form a subalgebra of Noether symmetries (Bokhari et al. in Int. J. Theor. Phys. 45:1063, 2006).

  16. Inflatable kill packers used in working over Kuwaiti wells

    SciTech Connect

    Miller, D. (Baker Oil Tools, Houston, TX (US)); Conover, G. (Baker Service Tools, Houston, TX (US))

    1992-03-09

    This paper reports on inflatable packers which are being used with great success in post-well capping workover operations in Kuwait oil fields. In mid-January, about one kill packer was being run per day. Use is expected to increase in March when a second post-capping crew arrives. Of several thousand unconventional ideas submitted to Kuwait Oil Co. (KOC) for controlling the well fires left in the aftermath of lst year's Gulf War, only about a dozen were actually used. Inflatable kill packers, designed and manufactured by Baker Service Tools and marketed by Baker Oil Tools, were one of the ideas that proved effective. The kill packers are modifications of Baker's inflatable packers that have successfully been used in capping producers on many blowouts throughout the world, including the Piper Alpha disaster in the North Sea and the Saga blowout offshore Norway.

  17. QFT on homothetic Killing twist deformed curved spacetimes

    E-print Network

    Schenkel, Alexander

    2010-01-01

    We study the quantum field theory (QFT) of a free, real and massless scalar field on self-similar symmetric spacetimes, which are deformed by an abelian Drinfel'd twist constructed from a Killing and a homothetic Killing vector field. In contrast to deformations solely by Killing vector fields, such as the Moyal-Weyl Minkowski spacetime, the equation of motion and Green's operators are deformed. We show that there is a *-algebra isomorphism between the QFT on the deformed and the formal power series extension of the QFT on the undeformed spacetime. We study the convergent implementation of our deformations for toy-models. For these models it is found that there is a *-isomorphism between the deformed Weyl algebra and a reduced undeformed Weyl algebra, where certain strongly localized observables are excluded. Thus, our models realize the intuitive physical picture that noncommutative geometry prevents arbitrary localization in spacetime.

  18. Novel method for monitoring genetically engineered microorganisms in the environment.

    PubMed

    Chaudhry, G R; Toranzos, G A; Bhatti, A R

    1989-05-01

    A method has been devised for directly detecting and monitoring genetically engineered microorganisms (GEMs) by using in vitro amplification of the target DNAs by a polymerase chain reaction and then hybridizing the DNAs with a specific oligonucleotide or DNA probe. A cloned 0.3-kilobase napier grass (Pennisetum purpureum) genomic DNA that did not hybridize to DNAs isolated from various microorganisms, soil sediments, and aquatic environments was inserted into a derivative of a 2,4-dichlorophenoxyacetic acid-degradative plasmid, pRC10, and transferred into Escherichia coli. This genetically altered microorganism, seeded into filter-sterilized lake and sewage water samples (10(4)/ml), was detected by a plate count method in decreasing numbers for 6 and 10 days of sample incubation, respectively. The new method detected the amplified unique marker (0.3-kilobase DNA) of the GEM even after 10 to 14 days of incubation. This method is highly sensitive (it requires only picogram amounts of DNA) and has an advantage over the plate count technique, which can detect only culturable microorganisms. The method may be useful for monitoring GEMs in complex environments, where discrimination between GEMs and indigenous microorganisms is either difficult or requires time-consuming tests. PMID:2667463

  19. Assessment of cellulolytic microorganisms in soils of Nevados Park, Colombia.

    PubMed

    Avellaneda-Torres, Lizeth Manuela; Pulido, Claudia Patricia Guevara; Rojas, Esperanza Torres

    2014-01-01

    A systematized survey was conducted to find soil-borne microbes that degrade cellulose in soils from unique ecosystems, such as the Superpáramo, Páramo, and the High Andean Forest in the Nevados National Natural Park (NNNP), Colombia. These high mountain ecosystems represent extreme environments, such as high levels of solar radiation, low atmospheric pressure, and extreme daily changes in temperature. Cellulolytic activity of the microorganisms was evaluated using qualitative tests, such as growth in selective media followed by staining with congo red and iodine, and quantitative tests to determine the activity of endoglucanase, ?-glucosidase, exoglucanase, and total cellulase. Microorganisms were identified using molecular markers, such as the 16S rRNA gene for bacteria and the internal transcribed spacer region (ITS) of ribosomal DNA for fungi. Multivariate statistical analysis (MVA) was used to select microorganisms with high cellulolytic capacity. A total of 108 microorganisms were isolated from the soils and, in general, the enzymatic activities of fungi were higher than those of bacteria. Our results also found that none of the organisms studied were able to degrade all the components of the cellulose and it is therefore suggested that a combination of bacteria and/or fungi with various enzymatic activities be used to obtain high total cellulolytic activity. This study gives an overview of the potential microorganism that could be used for cellulose degradation in various biotechnological applications and for sustainable agricultural waste treatment. PMID:25763024

  20. Astrobiological significance of microorganisms in permafrost and ice

    NASA Astrophysics Data System (ADS)

    Hoover, Richard B.

    1999-12-01

    Microorganisms of the permafrost, glaciers, and polar ice sheets of planet Earth provide analogs for microbial life forms that may be encountered on ice or permafrost of Mars, Europa, Callisto, Ganymede, or even asteroids or comets. Most bodies of our Solar System are frozen worlds. The microbiota of the terrestrial cryosphere help establish the thermal and temporal limitations of life on Earth and provide clues to of where and how we should search for evidence of life elsewhere in the Cosmos. Consequently, these life forms are relevant to Astrobiology. Cryopreserved microorganisms can remain viable (in deep anabiosis) in permafrost and ice for millions of years and may contain intact ancient DNA, lipids, enzymes, proteins and genes. Some microorganisms carry out metabolic processes in water films and brine, acidic, or alkaline channels in permafrost or ice at temperature far below 0 C. Complex microbial ecosystems may inhabit snow, ice-bubbles, and cryoconite holes on glaciers and the polar caps. At the NASA Marshall Space Flight Center we employed the Environmental Scanning Electron Microscope to study the morphology, ultra- microstructure and chemical composition of microorganisms in-situ in ancient permafrost and ice. In this paper we present images of cryopreserved microorganisms from deep ice cores above Lake Vostok and thermokarst ponds of the Fox Tunnel of Alaska.

  1. Capillary isoelectric focusing of native and inactivated microorganisms.

    PubMed

    Horká, M; Kubícek, O; R?zicka, F; Holá, V; Malinovská, I; Slais, K

    2007-07-01

    The research of microorganisms includes the development of methods for the inactivation of viruses and other microbes. It also means to efficiently eliminate the infectivity of microorganisms without damage of their integrity and structure. According to the results of the last 5 years the capillary electromigration techniques appear to be very perspective for the comparison of the methods applicable for inactivation in the diagnostics and study of the pathogens. In this paper we suggest the capillary isoelectric focusing of the model microorganisms, Escherichia coli, Staphylococcus epidermidis, Candida albicans and bacteriophage PhiX 174, native or inactivated by different procedures. UV detection and fluorometric detection for the dynamically modified microbes by pyrenebutanoate on the basis of the non-ionogenic tenside were used here. Isoelectric points of native and/or dynamically modified microorganisms and other properties were compared with those obtained after microorganisms inactivation. The segmental injection of the sample pulse enabled the reproducible and efficient capillary isoelectric focusing in different pH gradients. The low-molecular-weight pI markers were used for tracing of the pH gradient. PMID:17328903

  2. Humane killing of animals for disease control purposes.

    PubMed

    Thornber, P M; Rubira, R J; Styles, D K

    2014-04-01

    Killing for disease control purposes is an emotional issue for everyone concerned. Large-scale euthanasia or depopulation of animals may be necessary for the emergency control or eradication of animal diseases, to remove animals from a compromised situation (e.g. following flood, storm, fire, drought or a feed contamination event), to effect welfare depopulation when there is an oversupply due to a dysfunctional or closed marketing channel, or to depopulate and dispose of animals with minimal handling to decrease the risk of a zoonotic disease infecting humans. The World Organisation for Animal Health (OIE) developed international standards to provide advice on humane killing for various species and situations. Some fundamental issues are defined, such as competency of animal handling and implementation of humane killing techniques. Some of these methods have been used for many years, but novel approaches for the mass killing of particular species are being explored. Novel vaccines and new diagnostic techniques that differentiate between vaccinated and infected animals will save many animals from being killed as part of biosecurity response measures. Unfortunately, the destruction of affected livestock will still be required to control diseases whilst vaccination programmes are activated or where effective vaccines are not available. This paper reviews the principles of humane destruction and depopulation and explores available techniques with their associated advantages and disadvantages. It also identifies some current issues that merit consideration, such as legislative conflicts (emergency disease legislation versus animal welfare legislation, occupational health and safety), media issues, opinions on the future approaches to killing for disease control, and animal welfare. PMID:25000803

  3. Polymers used to direct kill fluids to blowout

    SciTech Connect

    Ely, J.W.; Holditch, S.A.

    1988-08-01

    In many reservoirs, it is difficult to establish communication between a relief well and a blowout well because of high fluid loss between the wells. In such cases, the polymer kill technique can be an important method to establish the required communication. This method will only work in very high permeability or fractured, vugular formations. However, these reservoirs are most likely to blowout at rates that will need a relief well. Once communication has been established, cheaper, less-viscous fluids can then be used to perform a dynamic kill. After this succeeds, drilling mud or other heavy fluids can be pumped to contain the well.

  4. Invading Phragmites australis stimulates methane emissions from North American tidal marshes

    NASA Astrophysics Data System (ADS)

    Mueller, Peter; Meschter, Justin E.; Hager, Rachel N.; Mozdzer, Thomas J.; Jensen, Kai; Langley, J. Adam; Baldwin, Andrew; Megonigal, J. Patrick

    2015-04-01

    Most studies concerned with invasive plant species focus on effects on biodiversity, while only few have investigated how the greenhouse gas balance of an ecosystem or, in particular, how methane emissions are affected by invasion driven shifts in plant species composition. In this study, conducted in brackish marsh sites of the Chesapeake Bay, United States, we investigated the effect of the none-native grass Phragmites australis invading native shortgrass communities on methane emissions. In situ gas flux measurements using static chambers were used to quantify methane emissions along transects of progressive invasion by Phragmites. Methane emissions were several fold higher in Phragmites stands than in adjacent native communities and increased with progressive invasion of Phragmites. Results of a mesocosm experiment support our field observations and show consistently higher methane emissions from mesocoms planted with Phragmites even at different hydrological conditions. Because tidal marshes, as blue carbon ecosystems, sequester soil carbon rapidly and emit methane slowly compared to other wetland ecosystems, they are increasingly recognized as having a high carbon value. Our results indicate that the replacement of native marsh communities by Phragmites may considerably change the green house gas balance of these ecosystems and thus lower their carbon sequestration value.

  5. Small RNA-based silencing strategies for transposons in the process of invading Drosophila species.

    PubMed

    Rozhkov, Nikolay V; Aravin, Alexei A; Zelentsova, Elena S; Schostak, Natalia G; Sachidanandam, Ravi; McCombie, W Richard; Hannon, Gregory J; Evgen'ev, Michael B

    2010-08-01

    Colonization of a host by an active transposon can increase mutation rates or cause sterility, a phenotype termed hybrid dysgenesis. As an example, intercrosses of certain Drosophila virilis strains can produce dysgenic progeny. The Penelope element is present only in a subset of laboratory strains and has been implicated as a causative agent of the dysgenic phenotype. We have also introduced Penelope into Drosophila melanogaster, which are otherwise naive to the element. We have taken advantage of these natural and experimentally induced colonization processes to probe the evolution of small RNA pathways in response to transposon challenge. In both species, Penelope was predominantly targeted by endo-small-interfering RNAs (siRNAs) rather than by piwi-interacting RNAs (piRNAs). Although we do observe correlations between Penelope transcription and dysgenesis, we could not correlate differences in maternally deposited Penelope piRNAs with the sterility of progeny. Instead, we found that strains that produced dysgenic progeny differed in their production of piRNAs from clusters in subtelomeric regions, possibly indicating that changes in the overall piRNA repertoire underlie dysgenesis. Considered together, our data reveal unexpected plasticity in small RNA pathways in germ cells, both in the character of their responses to invading transposons and in the piRNA clusters that define their ability to respond to mobile elements. PMID:20581131

  6. Small RNA-based silencing strategies for transposons in the process of invading Drosophila species

    PubMed Central

    Rozhkov, Nikolay V.; Aravin, Alexei A.; Zelentsova, Elena S.; Schostak, Natalia G.; Sachidanandam, Ravi; McCombie, W. Richard; Hannon, Gregory J.; Evgen'ev, Michael B.

    2010-01-01

    Colonization of a host by an active transposon can increase mutation rates or cause sterility, a phenotype termed hybrid dysgenesis. As an example, intercrosses of certain Drosophila virilis strains can produce dysgenic progeny. The Penelope element is present only in a subset of laboratory strains and has been implicated as a causative agent of the dysgenic phenotype. We have also introduced Penelope into Drosophila melanogaster, which are otherwise naive to the element. We have taken advantage of these natural and experimentally induced colonization processes to probe the evolution of small RNA pathways in response to transposon challenge. In both species, Penelope was predominantly targeted by endo-small-interfering RNAs (siRNAs) rather than by piwi-interacting RNAs (piRNAs). Although we do observe correlations between Penelope transcription and dysgenesis, we could not correlate differences in maternally deposited Penelope piRNAs with the sterility of progeny. Instead, we found that strains that produced dysgenic progeny differed in their production of piRNAs from clusters in subtelomeric regions, possibly indicating that changes in the overall piRNA repertoire underlie dysgenesis. Considered together, our data reveal unexpected plasticity in small RNA pathways in germ cells, both in the character of their responses to invading transposons and in the piRNA clusters that define their ability to respond to mobile elements. PMID:20581131

  7. Invading species in the Eel River, California: Successes, failures, and relationships with resident species

    USGS Publications Warehouse

    Brown, L.R.; Moyle, P.B.

    1997-01-01

    We examined invasions of non-native fishes into the Eel River, California. At least 16 species of fish have been introduced into the drainage which originally supported 12-14 fish species. Our study was prompted by the unauthorized introduction in 1979 of Sacramento squawfish, Ptychocheilus grandis, a large predatory cyprinid. From 1986 to 1990, we conducted growth and diet studies of squaw fish, conducted intensive surveys of the distribution and habitat associations of both native and introduced species, and examined the nature of species-habitat and interspecies relationships. We found no evidence for increased growth or expanded feeding habits, compared to native populations, of Sacramento squawfish as they invaded the Eel River drainage. Ten of the introduced species were well established, with four species limited to a reservoir and six species established in streams. The success or failure of introductions of stream species appeared to be a function of the ability of a species to survive the fluctuating, highly seasonal, flow regime. The present mixture of native and exotic species has not formed stable fish assemblages but it seems likely that four habitat-associated assemblages will develop. The overall effect of the successful species introductions has been to assemble a group of species, with some exceptions, that are native to and occur together in many California streams. The assemblages now forming are similar to those found in other California streams. The assemblage characterized by squawfish and suckers is likely to be resistant to invasion, in the absence of human caused habitat modifications.

  8. Recurrent lentigo maligna invading a skin graft successfully treated with Mohs' micrographic surgery.

    PubMed

    Cohen, L M; Zax, R H

    1996-03-01

    Lentigo maligna (LM) is a pigmented lesion occurring on sun-exposed skin that may become lentigo maligna melanoma (LMM). The tumor can behave in an aggressive fashion, causing significant cosmetic disfigurement, often extending significantly further than the clinical margin. Complete surgical excision is the treatment of choice. We describe a 74-year-old woman with a large LM of the left cheek, upper and lower eyelids, and preauricular skin that had recurred twice. The tumor was removed using Mohs' micrographic surgery (MMS) with rush permanent sections and was found to infiltrate extensively the split-thickness skin graft that had been placed five years earlier. LM can invade and replace a skin graft. Although destructive modalities and conventional surgery are recommended by some authors, MMS offers the greatest likelihood of cure, the ability to examine nearly 100 percent of the surgical margins, and maximal tissue sparing. Complete excision of LM at its earliest recognition may prevent invasive LMM and will limit cosmetic disfigurement. PMID:8882016

  9. Porphyromonas gingivalis invades human trophoblasts and inhibits proliferation by inducing G1 arrest and apoptosis

    PubMed Central

    Inaba, Hiroaki; Kuboniwa, Masae; Bainbridge, Brian; Yilmaz, Özlem; Katz, Joseph; Shiverick, Kathleen T.; Amano, Atsuo; Lamont, Richard J.

    2009-01-01

    Summary Porphyromonas gingivalis is an oral pathogen that is also associated with serious systemic conditions such as preterm delivery. Here we investigated the interaction between P. gingivalis and a cell line of extravillous trophoblasts (HTR-8) derived from the human placenta. P. gingivalis internalized within HTR-8 cells and inhibited proliferation through induction of arrest in the G1 phase of the cell cycle. G1 arrest was associated with decreased expression of cyclin D and of CDKs 2, 4 and 6. In addition, levels of CDK inhibitors p15, p16, p18 and p21 were increased following P. gingivalis infection. The amount of Rb was diminished by P. gingivalis, and transient overexpression of Rb, with concomitant upregulation of phospho-Rb, relieved P. gingivalis-induced G1 arrest. HTR-8 cells halted in the G1 phase became apoptotic, and apoptosis was accompanied by an increase in the ratio of Bax/Bcl-2 and increased activity of caspases 3, 7 and 9. HTR-8 cells infected with P. gingivalis also exhibited a sustained activation of ERK1/2, and knockdown of ERK1/2 activity with siRNA abrogated both G1 arrest and apoptosis. Thus, P. gingivalis can invade placental trophoblasts and induce G1 arrest and apoptosis through pathways involving ERK1/2 and its downstream effectors, properties that provide a mechanistic basis for pathogenicity in complications of pregnancy. PMID:19523155

  10. Alien Roadside Species More Easily Invade Alpine than Lowland Plant Communities in a Subarctic Mountain Ecosystem

    PubMed Central

    Lembrechts, Jonas J.; Milbau, Ann; Nijs, Ivan

    2014-01-01

    Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment. PMID:24586947

  11. Detection and genetic diversity of a heliothine invader (Lepidoptera: Noctuidae) from north and northeast of Brazil.

    PubMed

    Mastrangelo, T; Paulo, D F; Bergamo, L W; Morais, E G F; Silva, M; Bezerra-Silva, G; Azeredo-Espin, A M L

    2014-06-01

    The cotton bollworm, Helicoverpa armigera (Hübner), was recently introduced in Brazil. During the 2012-2013 harvest, producers reported reduced yields up to 35% on major crops. The economic losses reached US$ 1 billion only in western Bahia, triggering a phytosanitary crisis. The deficiencies in existing taxonomic keys to deal with the morphologically indistinct larvae of H. armigera and the native Helicoverpa zea (Boddie) constrained the detection of new incursions of this heliothine invader. This study explored the identity of heliothine larvae that were found infesting soybean- and corn-growing areas from Roraima state, northern Brazil, through sequences of the mitochondrial cytochrome c oxidase subunit I gene. The inter- and intraspecies sequence variations of DNA barcodes in H. armigera and H. zea were analyzed. The genetic diversity and population structure of the specimens from Roraima and two populations from Piauí and Bahia states, northeastern Brazil, were assessed by adding the cytochrome c oxidase subunit II gene to the analysis. Owing to the lack of studies on genetic introgression for the two species, the suitability of using three different nuclear genes to distinguish the two species was also investigated. The results showed strong evidence that the heliothine larvae from north and northeast of Brazil are conspecific with H. armigera, suggesting that this invasive moth has already crossed the Amazon basin. Surveys in the north of South America should start as soon as possible to monitor the entry or spread of this moth in the Caribbean, Central America, and the United States. PMID:25026655

  12. Despite spillover, a shared pathogen promotes native plant persistence in a cheatgrass-invaded grassland.

    PubMed

    Mordecai, Erin A

    2013-12-01

    How pathogen spillover influences host community diversity and composition is poorly understood. Spillover occurs when transmission from a reservoir host species drives infection in another host species. In cheatgrass-invaded grasslands in the western United States, a fungal seed pathogen, black fingers of death (Pyrenophora semeniperda), spills over from exotic cheatgrass (Bromus tectorum) to native perennial bunchgrasses such as squirreltail (Elymus elymoides). Previous theoretical work based on this system predicts that pathogens that spill over can favor either host coexistence, the exclusion of either host species, or priority effects, depending on species-specific transmission rates and pathogen tolerance. Here, these model predictions were tested by parameterizing a population growth model with field data from Skull Valley, Utah, USA. The model suggests that, across the observed range of demographic variation, the pathogen is most likely to provide a net benefit to squirreltail and a net cost to cheatgrass, though both effects are relatively weak. Although cheatgrass (the reservoir host) is more tolerant, squirreltail is far less susceptible to infection, and its long-lived adult stage buffers population growth against seed losses to the pathogen. This work shows that, despite pathogen spillover, the shared pathogen promotes native grass persistence by reducing exotic grass competition. Counterintuitively, the reservoir host does not necessarily benefit from the presence of the pathogen, and may even suffer greater costs than the nonreservoir host. Understanding the consequences of shared pathogens for host communities requires weighing species differences in susceptibility, transmission, and tolerance using quantitative models. PMID:24597221

  13. Surgical treatment of T3 lung cancer invading the chest wall.

    PubMed

    Beltrami, V; Bezzi, M; Illuminati, G; Forte, A; Angelici, A; Bertagni, A; Ciulli, A; Gallinaro, L; Lorenzotti, A; Montesano, G; Palumbo, P G; Prece, V

    1999-01-01

    Lung tumors invading the chest wall are classed as belonging to the T3 group and are considered potentially resectable. Their management, however, is controversial, and extrapleural resection, when possible, is preferred to en bloc resection which is regarded as a far more invasive and dangerous operation. Five year survival rates for completely resected cases range in the literature from 25 to 35%, but survival rates are much worse if lymph node metastases are present. These poor outcomes have prompted the development of combined surgical approaches: preoperative radiation therapy, with or without chemotherapy, has been used with an improvement in resectability rates, but only modest results in terms of median survival; in a number of case series, increased operative morbidity and mortality have been reported with this approach. The present report relates to 122 patients treated by en bloc (20 cases) or extrapleural (102 cases) resection, 31 of whom also received neoadjuvant treatment. The operative mortality was 4.6%. Median survival was 17 months after en bloc resection and 19 months after extrapleural resection. Though no statistically significant difference was found, extrapleural resection would appear to yield better results than the en bloc procedure. PMID:10742890

  14. Reproductive Plasticity in Freshwater Invader: From Long-Term Sperm Storage to Parthenogenesis

    PubMed Central

    Bu?i?, Miloš; Kouba, Antonín; Kozák, Pavel

    2013-01-01

    Orconectes limosus, a North American crayfish species, is one of the most important aquatic invaders in European inland waters. Despite more than 120 years occurrence in Europe and intense research, there are still gaps in knowledge of its life history and ecology. Investigation into O. limosus invasive success requires identifying the mechanisms that enabled them to establish dense and widespread populations from small initial numbers without observable limitation by an introduction bottleneck. In part, O. limosus success may lie in its ability to reproduce by facultative parthenogenesis. Moreover, there are possible other mating scenarios, because of two mating seasons (autumn and spring) in O. limosus. This work investigated the effect of four reproductive scenarios (autumn mating only, spring mating only, autumn and spring mating, and without mating) on the reproductive success of O. limosus. Females successfully reproduced in all tested mating regimes using parthenogenesis as well as log term sperm storage. This reproductive plasticity likely facilitates the overwhelming success of O. limosus spread and establishment in new localities. It can explain the spread of O. limosus from the initial introduction of 90 specimens to most of continental Europe and Great Britain. These conclusions imply a serious threat, not only for autochthonous European astacofauna, but for other aquatic organisms as well as entire ecosystems. PMID:24204886

  15. Early observations on an emerging Great Lakes invader Hemimysis anomala in Lake Ontario

    USGS Publications Warehouse

    Walsh, Maureen G.; Lantry, Brian F.; Boscarino, Brent; Bowen, Kelly; Gerlofsma, Jocelyn; Schaner, Ted; Back, Richard; Questel, Jennifer; Smythe, A. Garry; Cap, Roberta; Goehle, Michael; Young, Bryan; Chalupnicki, Marc; Johnson, James H.; McKenna, James E.

    2010-01-01

    Hemimysis anomala, a Ponto-Caspian littoral mysid, is an emerging Great Lakes invader that was discovered in Lakes Michigan and Ontario in 2006. Similar to the native mysid Mysis diluviana, Hemimysis exhibits a diel vertical migration pattern but generally inhabits shallower and warmer waters than M. diluviana. Because basic information on the distribution, habitat use, and biology of Hemimysis in the Great Lakes is scarce, the potential for food web disruption by Hemimysis cannot easily be predicted. Preliminary observations indicate widespread invasion of Hemimysis in Lake Ontario. In this study, we confirm the presence of Hemimysis at sites spanning the northern and southern shores of Lake Ontario and the presence of the individuals during winter months. In one horizontal tow in November 2007, over 26,000 individuals were collected with a length range of 4.4 to 9.0. mm and an average caloric density of 611. cal/g wet weight. The most effective methods for sampling Hemimysis were horizontal tows with either a zooplankton net in the water column or a benthic sled near the lake bottom. Although more quantitative data on the life history and distribution of this species is necessary, our preliminary observations support the prediction that the potential for Hemimysis to impact the nearshore food web in Lake Ontario appears high.

  16. Plant communities in harsh sites are less invaded: a summary of observations and proposed explanations

    PubMed Central

    Zefferman, Emily; Stevens, Jens T.; Charles, Grace K.; Dunbar-Irwin, Mila; Emam, Taraneh; Fick, Stephen; Morales, Laura V.; Wolf, Kristina M.; Young, Derek J. N.; Young, Truman P.

    2015-01-01

    Plant communities in abiotically stressful, or ‘harsh’, habitats have been reported to be less invaded by non-native species than those in more moderate habitats. Here, we synthesize descriptive and experimental evidence for low levels of invasion in habitats characterized by a variety of environmental stressors: low nitrogen; low phosphorus; saline, sodic or alkaline soils; serpentine soils; low soil moisture; shallow/rocky soils; temporary inundation; high shade; high elevation; and high latitude. We then discuss major categories of hypotheses to explain this pattern: the propagule limitation mechanism suggests invasion of harsh sites is limited by relatively low arrival rates of propagules compared with more moderate habitats, while invasion resistance mechanisms suggest that harsh habitats are inherently less invasible due to stressful abiotic conditions and/or increased effects of biotic resistance from resident organisms. Both propagule limitation and invasion resistance may simultaneously contribute to low invadedness of harsh sites, but the management implications of these mechanisms differ. If propagule limitation is more important, managers should focus on reducing the likelihood of propagule introductions. If invasion resistance mechanisms are in play, managers should focus on restoring or maintaining harsh conditions at a site to reduce invasibility. PMID:26002746

  17. An Archaeal Immune System Can Detect Multiple Protospacer Adjacent Motifs (PAMs) to Target Invader DNA*

    PubMed Central

    Fischer, Susan; Maier, Lisa-Katharina; Stoll, Britta; Brendel, Jutta; Fischer, Eike; Pfeiffer, Friedhelm; Dyall-Smith, Mike; Marchfelder, Anita

    2012-01-01

    The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) system provides adaptive and heritable immunity against foreign genetic elements in most archaea and many bacteria. Although this system is widespread and diverse with many subtypes, only a few species have been investigated to elucidate the precise mechanisms for the defense of viruses or plasmids. Approximately 90% of all sequenced archaea encode CRISPR/Cas systems, but their molecular details have so far only been examined in three archaeal species: Sulfolobus solfataricus, Sulfolobus islandicus, and Pyrococcus furiosus. Here, we analyzed the CRISPR/Cas system of Haloferax volcanii using a plasmid-based invader assay. Haloferax encodes a type I-B CRISPR/Cas system with eight Cas proteins and three CRISPR loci for which the identity of protospacer adjacent motifs (PAMs) was unknown until now. We identified six different PAM sequences that are required upstream of the protospacer to permit target DNA recognition. This is only the second archaeon for which PAM sequences have been determined, and the first CRISPR group with such a high number of PAM sequences. Cells could survive the plasmid challenge if their CRISPR/Cas system was altered or defective, e.g. by deletion of the cas gene cassette. Experimental PAM data were supplemented with bioinformatics data on Haloferax and Haloquadratum. PMID:22767603

  18. The role of microorganisms in coral health, disease and evolution.

    PubMed

    Rosenberg, Eugene; Koren, Omry; Reshef, Leah; Efrony, Rotem; Zilber-Rosenberg, Ilana

    2007-05-01

    Coral microbiology is an emerging field, driven largely by a desire to understand, and ultimately prevent, the worldwide destruction of coral reefs. The mucus layer, skeleton and tissues of healthy corals all contain large populations of eukaryotic algae, bacteria and archaea. These microorganisms confer benefits to their host by various mechanisms, including photosynthesis, nitrogen fixation, the provision of nutrients and infection prevention. Conversely, in conditions of environmental stress, certain microorganisms cause coral bleaching and other diseases. Recent research indicates that corals can develop resistance to specific pathogens and adapt to higher environmental temperatures. To explain these findings the coral probiotic hypothesis proposes the occurrence of a dynamic relationship between symbiotic microorganisms and corals that selects for the coral holobiont that is best suited for the prevailing environmental conditions. Generalization of the coral probiotic hypothesis has led us to propose the hologenome theory of evolution. PMID:17384666

  19. Swimming of microorganism and the string- and membrane- like algebra

    E-print Network

    Kawamura, M; Nojiri, S; Masako KAWAMURA; Sugamoto, Akio; Nojiri, Shin'ichi

    1994-01-01

    Swimming of microorganisms is further developed from a viewpoint of strings and membranes swimming in the incompressible fluid of low Reynolds number. In our previous paper the flagellated motion was analyzed in two dimensional fluid, by using the method developed in the ciliated motion with the Joukowski transformation. This method is further refined by incorporating the inertia term of fluid as the perturbation. Understanding of the algebra controlling the deformation of microorganisms in the fluid is further developed, obtaining the central extension of the algebra with the help of the recent progress on the W_{1+\\infty} algebra. Our previous suggestion on the usefulness of the N-point string- and membrane-like amplitudes for studying the collective swimming motion of N-1 microorganisms is also examined.

  20. Swimming of Microorganism and the String- and Membrane- like Algebra

    E-print Network

    Masako Kawamura; Akio Sugamoto; Shin'ichi Nojiri

    1994-06-16

    Swimming of microorganisms is further developed from a viewpoint of strings and membranes swimming in the incompressible fluid of low Reynolds number. In our previous paper the flagellated motion was analyzed in two dimensional fluid, by using the method developed in the ciliated motion with the Joukowski transformation. This method is further refined by incorporating the inertia term of fluid as the perturbation. Understanding of the algebra controlling the deformation of microorganisms in the fluid is further developed, obtaining the central extension of the algebra with the help of the recent progress on the $W_{1+\\infty}$ algebra. Our previous suggestion on the usefulness of the $N$-point string- and membrane-like amplitudes for studying the collective swimming motion of $N-1$ microorganisms is also examined.