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Unique Mode (unique + mode)
Selected AbstractsTopical dose delivery in the reptilian egg treatment modelENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2007Jennifer K. Muller Abstract Developing assays to detect endocrine-mediated toxicity from in ovo or in utero exposure is a current challenge in regulatory toxicology. Some species of reptiles exhibiting a unique mode of sex determination, in which the incubation temperature during a critical period determines gonadal sex, have been explored as an in ovo model to screen environmental contaminants for endocrine effects. We critically review published egg-exposure studies and conclude that data regarding the pharmacokinetics of topically applied substances are insufficient to validate dose,response relationships for the effects of chemicals on in ovo endocrine function or gender determination in reptiles. The insufficiencies in these data largely result from methodological failures, including lack of measurement verification, failure to investigate and control extraneous factors affecting the measurements, and lack of independent replication of results. Considerable additional research will be necessary to alleviate these methodological inadequacies. Given the current status of the data, topical treatment of reptilian eggs cannot be considered to be a valid means of establishing causal relationships between chemical treatment and biological outcome. [source] Structural determination of the O-chain polysaccharide from Agrobacterium tumefaciens, strain DSM 30205FEBS JOURNAL, Issue 12 2002Cristina De Castro Agrobacterium tumefaciens is a Gram-negative, phytopathogenic bacterium and is characterized by an unique mode of action on dicotyledonous plants: it is able to genetically modify the host, and because of this feature, it is used as a tool for transgenic plants. Many experiments have demonstrated that lipopolysaccharides (LPSs) play an important role for the disease development, as they are involved in the adhesion process of the bacterium on the plant cell wall. Despite the wealth of information on the role of LPS on phytopathogenesis, the present paper appears as the first report on the molecular primary structure of the O-chain produced from Agrobacterium. Its repeating unit was determined by means of chemical and spectroscopical analysis, and has the following structure: (3)-,- d -Araf -(1,3)-,- l -Fucp -(1,. [source] Putative Nitrogen Sensing Systems in Higher PlantsJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 8 2006Hon-Ming Lam Abstract Nitrogen (N) metabolism is essential for the biosynthesis of vital biomolecules. N status thus exerts profound effects on plant growth and development, and must be closely monitored. In bacteria and fungi, a few sophisticated N sensing systems have been extensively studied. In animals, the ability to receive amino acid signals has evolved to become an integral part of the nervous coordination system. In this review, we will summarize recent developments in the search for putative N sensing systems in higher plants based on homologous systems in bacteria, fungi, and animals. Apparently, although plants have separated and diversified from other organisms during the evolution process, striking similarities can be found in their N sensing systems compared with those of their counterparts; however, our understanding of these systems is still incomplete. Significant modifications of the N sensing systems (including cross-talk with other signal transduction pathways) in higher plants may be a strategy of adaptation to their unique mode of life. (Managing editor: Ping He) [source] Isofurans, but not F2 -isoprostanes, are increased in the substantia nigra of patients with Parkinson's disease and with dementia with Lewy body diseaseJOURNAL OF NEUROCHEMISTRY, Issue 3 2003Joshua P. Fessel Abstract F2 -isoprostanes (F2 -IsoPs) are well-established sensitive and specific markers of oxidative stress in vivo. Isofurans (IsoFs) are also products of lipid peroxidation, but in contrast to F2 -IsoPs, their formation is favored when oxygen tension is increased in vitro or in vivo. Mitochondrial dysfunction in Parkinson's disease (PD) may not only lead to oxidative damage to brain tissue but also potentially result in increased intracellular oxygen tension, thereby influencing relative concentrations of F2 -IsoPs and IsoFs. In this study, we attempted to compare the levels of F2 -IsoPs and IsoFs esterified in phospholipids in the substantia nigra (SN) from patients with PD to those of age-matched controls as well as patients with other neurodegenerative diseases, including dementia with Lewy body disease (DLB), multiple system atrophy (MSA), and Alzheimer's disease (AD). The results demonstrated that IsoFs but not F2 -IsoPs in the SN of patients with PD and DLB were significantly higher than those of controls. Levels of IsoFs and F2 -IsoPs in the SN of patients with MSA and AD were indistinguishable from those of age-matched controls. This preferential increase in IsoFs in the SN of patients with PD or DLB not only indicates a unique mode of oxidant injury in these two diseases but also suggests different underlying mechanisms of dopaminergic neurodegeneration in PD and DLB from those of MSA. [source] The pharmacology of radiolabeled cationic antimicrobial peptidesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2008Carlo P.J.M. Brouwer Abstract Cationic antimicrobial peptides are good candidates for new diagnostics and antimicrobial agents. They can rapidly kill a broad range of microbes and have additional activities that have impact on the quality and effectiveness of innate responses and inflammation. Furthermore, the challenge of bacterial resistance to conventional antibiotics and the unique mode of action of antimicrobial peptides have made such peptides promising candidates for the development of a new class of antibiotics. This review focuses on antimicrobial peptides as a topic for molecular imaging, infection detection, treatment monitoring and additionally, displaying microbicidal activities. A scintigraphic approach to studying the pharmacokinetics of antimicrobial peptides in laboratory animals has been developed. The peptides were labeled with technetium-99m and, after intravenous injection into laboratory animals, scintigraphy allowed real-time, whole body imaging and quantitative biodistribution studies of delivery of the peptides to the various body compartments. Antimicrobial peptides rapidly accumulated at sites of infection but not at sites of sterile inflammation, indicating that radiolabeled cationic antimicrobial peptides could be used for the detection of infected sites. As the number of viable micro-organisms determines the rate of accumulation of these peptides, radiolabeled antimicrobial peptides enabled to determine the efficacy of antibacterial therapy in animals to be monitored as well to quantify the delivery of antimicrobial peptides to the site of infection. The scintigraphic approach provides to be a reliable method for investigating the pharmacokinetics of small cationic antimicrobial peptides in animals and offers perspective for diagnosis of infections, monitoring antimicrobial therapy, and most important, alternative antimicrobial treatment infections with multi-drug resistant micro-organisms in humans. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci [source] A floral organ moving like a caterpillar for pollinatingJOURNAL OF SYSTEMATICS EVOLUTION, Issue 2 2010Zhong-Jian LIU Abstract A new pollination mechanism is reported of an orchid species, Bulbophyllum penicillium, based on a field observation in Southeast Yunnan of China. This species has a sensitive lip, and there is a distance of 2,3 mm between it and column apex. Once the lip is touched by a landing insect, it will move up and down or swing left and right continuously, just like a moving caterpillar. By suck a lip movement, the pollinator, a very small fruit fly (Drosophila sp.) ca. 1 mm in height, will be pressed toward the column apex where anther and stigma are located, and then cross-pollination takes place. This unique mode of pollination, depending on the movement of lip rather than insect itself, has never been found before in either Orchidaceae or other families of angiosperms. [source] A unique mode of parasitism in the conifer coral tree Parasitaxus ustus (Podocarpaceae)PLANT CELL & ENVIRONMENT, Issue 10 2005TAYLOR S. FEILD ABSTRACT Almost all parasitic plants, including more than 3000 species, are angiosperms. The only suggested gymnosperm exception is the New Caledonian conifer, Parasitaxus ustus, which forms a bizarre graft-like attachment to the roots of another conifer Falcatifolium taxoides. Yet, the degree of resource dependence of Parasitaxus on Falcatifolium has remained speculative. Here we show that Parasitaxus is definitively parasitic, but it displays a physiological habit unlike any known angiosperm parasite. Despite possessing chloroplasts, it was found that the burgundy red shoots of Parasitaxus lack significant photosynthetic electron transport. However unlike non-photosynthetic angiosperm parasites (holoparasites), tissues of Parasitaxus are considerably enriched in 13carbon relative to its host. In line with anatomical observations of fungal hyphae embedded in the parasite/host union, stable carbon isotopic measurements indicate that carbon transport from the host to Parasitaxus most likely involves a fungal partner. Therefore, Parasitaxus parallels fungus-feeding angiosperms (mycoheterotrophs) that steal carbon from soil mycorrhizal fungi. Yet with its tree-like habit, association with fungi residing within the host union, high stomatal conductance, and low water potential, it is demonstrated that Parasitaxus functions unlike any known angiosperm mycoheterotroph or holoparasite. Parasitaxus appears to present a unique physiological chimera of mistletoe-like water relations and fungal-mediated carbon trafficking from the host. [source] Touch and American ReligionsRELIGION COMPASS (ELECTRONIC), Issue 4 2009Candy Gunther Brown The sense of touch plays an important role in many American religious practices. Yet dismissals of touch as an inferior mode of perception and reliance on textual sources that ignore touch have shaped research agendas. This essay identifies theories articulated by philosophical phenomenologists, students of ritual and performance studies, historians and anthropologists of art and architecture, neuroscientists, and feminist scholars that envision touch as a unique mode of gaining knowledge about the world and oneself and stimulating ethical behavior by working directly on the emotions to motivate empathetic, compassionate concern for others. The essay suggests how touch-oriented theories can aid the development of research areas in American religions where scholars have already begun fruitful explorations of tactility: studies of religious embodiment and ritual and of pain and its alleviation through divine healing or Complementary and Alternative Medicine (CAM). [source] Toxicity and disruption of midgut physiology in larvae of the European corn borer, Ostrinia nubilalis, by anion transporter blockersARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2009Dhana Raj Boina Abstract In this study, four blockers of anion transporters (ATs) belonging to four different classes of organic acids, including DIDS (4, 4'-diisothiocyanatostilbene-2, 2'- disulfonic acid; a stilbene disulfonic acid), NPPB [(5-nitro-2-(3-phenylpropylamino) benzoic acid; an anthranilic acid)], 9-AC (anthracene-9-carboxylic acid; an aromatic carboxylic acid), and IAA-94 (indanyloxy acetic acid; an indanyloxy alkanoic acid), were tested for their toxicity against the European corn borer (ECB), Ostrinia nubilalis. All the AT blockers inhibited the growth of larvae, increased the developmental time, and decreased survival compared to controls, when second-instar ECB larvae were fed for seven days on treated diet. In general, DIDS and NPPB were the most active compounds, with the rank order of activity being DIDS>NPPB>IAA-94>9-AC. All the AT blockers decreased the midgut alkalinity in fifth-instar larvae when fed for 3,h on treated diet. Effective concentrations required for 50% decrease in midgut alkalinity (EC50) ranged between 29.1 and 41.2,ppm and the rank order of activity was NPPB>DIDS>IAA-94>9-AC. Similarly, all the tested AT blockers inhibited 36Cl, uptake from the midgut lumen in fifth-instar larvae when fed for 3,h on treated diet. Concentrations required for 50% inhibition of 36Cl, uptake (IC50) ranged between 7.4 and 11.0,ppm and the rank order of activity was DIDS>NPPB>9-AC >IAA-94. Modest to highly strong positive correlations observed among growth, midgut alkalinity, and midgut Cl, ion transport in AT blocker,fed larvae suggested that these effects are causally related to each other. Finally, AT blockers have the potential to become good candidates for development of insecticides with a unique mode of action. © 2009 Wiley Periodicals, Inc. [source] Low population differentiation and high genetic diversity in the invasive species Carduus acanthoides L. (Asteraceae) within its native range in the Czech RepublicBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2009BOHUMIL MANDÁK Colonizing species are predicted to suffer from reductions in genetic diversity during founding events. Although there is no unique mode of reproduction that is characteristic of successful plant colonizers, many of them are predominantly self-fertilizing or apomictic species, and almost all outcrossing colonizers are self-compatible. Carduus acanthoides comprises a species of disturbed habitats with wind-dispersed seeds that colonizes open spaces of various sizes. Population genetic diversity was expressed by assessing patterns of variation at nine putatively neutral allozyme loci within and among 20 natural populations in its native distribution range in the Czech Republic. Overall, C. acanthoides displayed high levels of genetic diversity compared to other herbaceous plants. The percentage of polymorphic loci was 84.5, with values of 2.37, 0.330, and 0.364 for the mean number of alleles per polymorphic locus (A), observed heterozygosity (Ho), and expected heterozygosity (He), respectively. There was only weak evidence of inbreeding within populations (f = 0.097) and very low genetic differentiation among populations (, = 0.085). Analyses of the data provide strong evidence for isolation-by-distance for the whole study area. Even the colonizing species, C. acanthoides, currently supports a substantial amount of allozyme variation at both the species and population levels. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 596,607. [source] Voltage-dependent inhibition of the muscarinic cationic current in guinea-pig ileal cells by SK&F 96365BRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2000A V Zholos The effects of SK&F 96365 on cationic current evoked either by activating muscarinic receptors with carbachol or by intracellularly applied GTP,S (in the absence of carbachol) were studied using patch-clamp recording techniques in single guinea-pig ileal smooth muscle cells. SK&F 96365 reversibly inhibited the muscarinic receptor cationic current in a concentration-, time- and voltage-dependent manner producing concomitant alteration of the steady-state I-V relationship shape which could be explained by assuming that increasing membrane positivity increased the affinity of the blocker. The inhibition was similar for both carbachol- and GTP,S-evoked currents suggesting that the cationic channel rather than the muscarinic receptor was the primary site of the SK&F 96365 action. Increased membrane positivity induced additional rapid inhibition of the cationic current by SK&F 96365 which was more slowly relieved during membrane repolarization. Both the inhibition and disinhibition time course could be well fitted by a single exponential function with the time constants decreasing with increasing positivity for the inhibition (e -fold per about 12 mV) and approximately linearly decreasing with increasing negativity for the disinhibition. At a constant SK&F 96365 concentration, the degree of cationic current inhibition was a sigmoidal function of the membrane potential with a potential of half-maximal increase positive to about +30 mV and a slope factor of about ,13 mV. Increasing the duration of voltage steps at ,80 or at 80 mV, increased the percentage inhibition; the degree of inhibition was almost identical at both potentials providing evidence that the same cationic channel was responsible for the cationic current both at negative and at positive potentials. It is concluded that the distinctive and unique mode of SK&F 96365 action on the muscarinic receptor cationic channel is a valuable tool in future molecular biology studies of this channel. British Journal of Pharmacology (2000) 129, 695,702; doi:10.1038/sj.bjp.0703115 [source] Thymus-leukemia antigen (TL) as a major histocompatibility complex (MHC) class Ib molecule and tumor-specific antigenCANCER SCIENCE, Issue 6 2004Kunio Tsujimura Mouse thymus-leukemia antigens (TL) belong to the family of major histocompatibility complex (MHC) class Ib antigens and have a unique mode of expression, i.e., in contrast to other MHC class Ib or la antigens, they are found restricted to the intestines in all mouse strains, but also in the thymus of certain strains (TL+ strains). Nevertheless, a proportion of T lymphomas/leukemias in strains that do not express TL in the thymus (TL, strains) feature TL as a tumor antigen. TL was originally defined serologically, but subsequently we have succeeded in generating T cell receptor (TCR) ,, and ,, cytotoxic T lymphocytes (CTL) recognizing TL. By use of TL tetramers free from peptides and transfectants expressing various TL/H-2 chimeric molecules, we have been able to show that TL-specific CTL recognize the ,1 /,2 domain of TL without any additional antigen molecules. We previously reported that one of TL's functions in the thymus is positive selection of TCR,, CTL. Recent studies with TL tetramers revealed that they can bind to normal intestinal intraepithelial lymphocytes (ilEL) and thymocytes in a CD8-dependent, but TCR/CD3-independent manner, while their binding to TL-specific CTL is TCR/CD3-and CDS-dependent. The possible significance of these findings in relation to the roles of TL in the intestines is discussed. We have long been interested in TL as a model tumor antigen which shares characteristics with human differentiation tumor antigens, and we have demonstrated that growth of TL+ lymphoma cells in vivo is suppressed by immunization with TL+ skin or dendritic cells (DC) from TL transgenic mice. In addition, anti-tumor effects against TL+ T lymphomas were obtained by adoptive transfer of TL tetramer strongly-positive TL-specific CTLs. [source] THE CITY AS BARRACKS: Freetown, Monrovia, and the Organization of Violence in Postcolonial African CitiesCULTURAL ANTHROPOLOGY, Issue 3 2007DANNY HOFFMAN Responding to characterizations of the postcolonial African city as a negative space, theorists of African urban processes have begun to focus on the city's unique modes of production. But what does this emphasis on productive capacity mean if "the city" is not Johannesburg or Nairobi but the West African urban warscape of Freetown or Monrovia? I explore that question by examining how the labor of male urban youth is organized according to the logic of the barracks. I suggest that these West African capitals make labor simultaneously available for use on regional battlefields or mines, logging camps, or rubber plantations. Focusing on the Brookfields Hotel in central Freetown and Monrovia's Duala neighborhood underscores how urban spaces are increasingly configured by the structure and function of the barracks: as spaces for the organization and deployment of violent labor. [source] | ||||||||||||||||||||||||||||