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Oral Secretions (oral + secretion)

Distribution by Scientific Domains

Life Sciences	85%

Selected Abstracts

Bacteria in oral secretions of an endophytic insect inhibit antagonistic fungi

ECOLOGICAL ENTOMOLOGY, Issue 6 2006
YASMIN J. CARDOZA
Abstract 1.,Colonisation of host trees by an endophytic herbivore, the spruce beetle, Dendroctonus rufipennis, is accompanied by invasion of its galleries by a number of fungal species. Four of these associated species were identified as Leptographium abietinum, Aspergillus fumigatus, Aspergillus nomius, and Trichoderma harzianum. 2.,Trichoderma and Aspergillus significantly reduced spruce beetle survival and reproduction in controlled assays. 3.,A previously undescribed behaviour was observed, in which spruce beetle adults exuded oral secretions, especially within fungus-pervaded galleries. 4.,These oral secretions inhibited the growth of fungi except A. nomius, and disrupted the morphology of the latter. Administration of these secretions indicated a dose-dependent inhibitory effect. 5.,Oral secretions cultured on microbiological media yielded substantial bacterial growth. 6.,Filter-sterilised secretions failed to inhibit fungal growth, evidence that the bacteria are responsible for the antifungal activity. 7.,Nine bacterial isolates belonging to the Actinobacteria, Firmicutes, Gammaproteobacteria, and Betaproteobacteria taxa were obtained from the secretions. 8.,Bacterial isolates showed species-specific inhibitory activity against the four fungi antagonistic to spruce beetle. The bacterium with the strongest fungal inhibition activity was the actinomycete Micrococcus luteus. 9.,The production of bark beetle secretions containing bacteria that inhibit fungal growth is a novel finding. This suggests an additional level of complexity to ecological associations among bark beetles, conifers, and microorganisms, and an important adaptation for colonising subcortical tissue. [source]

Root growth dynamics of Nicotiana attenuata seedlings are affected by simulated herbivore attack

PLANT CELL & ENVIRONMENT, Issue 10 2007
GRÉGOIRE M. HUMMEL
ABSTRACT Many studies demonstrate resource-based trade-offs between growth and defence on a large timescale. Yet, the short-term dynamics of this growth reaction are still completely unclear, making it difficult to explain growth-defence trade-offs mechanistically. In this study, image-based non-destructive methods were used to quantify root growth reactions happening within hours following simulated herbivore attack. The induction of wound reactions in Nicotiana attenuata in the seedling stage led to transiently decreased root growth rates. Application of the oral secretion of the specialist herbivore Manduca sexta to the leaves led to a transient decrease in root growth that was more pronounced than if a mere mechanical wounding was imposed. Root growth reduction was more pronounced than leaf growth reduction. When fatty acid,amino acid conjugates (FACs) were applied to wounds, root growth reduction occurred in the same intensity as when oral secretion was applied. Timing of the transient growth reduction coincided with endogenous bursts of jasmonate (JA) and ethylene emissions reported in literature. Simulation of a wound response by applying methyl jasmonate (MeJA) led to more prolonged negative effects on root growth. Increased nicotine concentrations, trichome lengths and densities were observed within 72 h in seedlings that were treated with MeJA or that were mechanically wounded. Overall, these reactions indicate that even in a very early developmental stage, the diversion of plant metabolism from primary (growth-sustaining) to secondary (defence-related) metabolism can cause profound alterations of plant growth performance. [source]

Bacteria in oral secretions of an endophytic insect inhibit antagonistic fungi

Anticholinergics and Ketamine Sedation in Children: A Secondary Analysis of Atropine Versus Glycopyrrolate

ACADEMIC EMERGENCY MEDICINE, Issue 2 2010
Steven M. Green MD
Abstract Objectives:, Adjunctive anticholinergics are commonly administered during emergency department (ED) ketamine sedation in children under the presumption that drying oral secretions should decrease the likelihood of airway and respiratory adverse events. Pharmacologic considerations suggest that glycopyrrolate might exhibit a superior adverse effect profile to atropine. The authors contrasted the adverse events noted with use of each of these anticholinergics in a large multicenter observational database of ketamine sedations. Methods:, This was a secondary analysis of an observational database of 8,282 ED ketamine sedations assembled from 32 prior series. The authors compared the relative incidence of six adverse events (airway and respiratory adverse events, laryngospasm, apnea, emesis, recovery agitation, and clinically important recovery agitation) between children who received coadministered atropine, glycopyrrolate, or no anticholinergic. Multivariable analysis using the specific anticholinergic as a covariate was performed, while controlling for other known predictors. Results:, Atropine was associated with less vomiting (5.3%) than either glycopyrrolate (10.7%) or no anticholinergic (11.4%) in both unadjusted and multivariable analyses. Glycopyrrolate was associated with significantly more airway and respiratory adverse events (6.4%) than either atropine (3.3%) or no anticholinergic (3.0%) and similarly more clinically important recovery agitation (2.1% vs. 1.2 and 1.3%). There were, however, no differences noted in odds of laryngospasm and apnea. Conclusions:, This secondary analysis unexpectedly found that the coadministered anticholinergic atropine exhibited a superior adverse event profile to glycopyrrolate during ketamine sedation. Any such advantage requires confirmation in a separate trial; however, our data cast doubt on the traditional premise that glycopyrrolate might be superior. Further, neither anticholinergic showed efficacy in decreasing airway and respiratory adverse events. ACADEMIC EMERGENCY MEDICINE 2010; 17:157,162 © 2010 by the Society for Academic Emergency Medicine [source]

EBNA1 sequences in Argentinean pediatric acute and latent Epstein,Barr virus infection reflect circulation of novel South American variants,

JOURNAL OF MEDICAL VIROLOGY, Issue 10 2010
Mario Alejandro Lorenzetti
Abstract Epstein,Barr virus (EBV) is related to the development of lymphomas and is also the etiological agent for infectious mononucleosis (IM). Sequence variation of the EBNA1 gene, consistently expressed in all EBV-positive cells, has been widely studied. Based on the amino acid at codon 487 five major EBNA1 variants have been described, two closely related prototypic variants (P-ala and P-thr) and three variant sequences (V-leu, V-val, and V-pro). Sub-variants were then further classified based on mutations other than the originally described. While several studies proposed associations with tumors and/or anatomical compartments, others argued in favor of a geographical distribution of these variants. In the present study, EBNA1 variants in 11 pediatric patients with IM and 19 pediatric EBV lymphomas from Argentina were compared as representatives of benign and malignant infection in children, respectively. A 3-month follow-up study of EBNA1 variants in peripheral blood cells and in oral secretions of patients with IM was performed. A new V-ala variant which includes five V-ala sub-variants and three new V-leu sub-variants was described. These data favor the geographical association hypothesis since no evidence for a preferential compartment distribution of EBNA1 variants and sub-variants was found. This is the first study to characterize EBNA1 variants in pediatric patients with infection mononucleosis worldwide. J. Med. Virol. 82:1730,1738, 2010. © 2010 Wiley-Liss, Inc. [source]

Herbivory-induced signalling in plants: perception and action

PLANT CELL & ENVIRONMENT, Issue 9 2009
JIANQIANG WU
ABSTRACT Plants and herbivores have been interacting for millions of years. Over time, plants have evolved mechanisms to defend against herbivore attacks. Herbivore-challenged plants reconfigure their metabolism to produce compounds that are toxic, repellant or anti-digestive for the herbivores. Some compounds are volatile signals that attract the predators of herbivores. All these responses are tightly regulated by a signalling network triggered by the plant's perception machinery. Several compounds that specifically elicit herbivory-induced responses in plants have been isolated from herbivore oral secretions and oviposition fluids. Elicitor perception is rapidly followed by cell membrane depolarization, calcium influx and mitogen-activated protein kinase (MAPK) activation; plants also elevate the concentrations of reactive oxygen and nitrogen species, and modulate phytohormone levels accordingly. In addition to these reactions in the herbivore-attacked regions of a leaf, defence responses are also mounted in unattacked parts of the attacked leaf and as well in unattacked leaves. In this review, we summarize recent progress in understanding how plants recognize herbivory, the involvement of several important signalling pathways that mediate the responses to herbivore attack and the signals that transduce local into systemic responses. [source]