Genes responsible for anaerobic fumarate and arginine metabolism are involved in growth suppression in Salmonella enterica serovar Typhimurium in vitro, without influencing colonisation inhibition in the chicken in vivo     

Nógrády N  Imre A  Rychlik I  Barrow PA  Nagy B 《Veterinary microbiology》2003,97(3-4):191-199

From a collection of over 2800 Salmonella enterica subspecies Enterica serotype Typhimurium F98 Tn5-TC1 insertion mutants 14 were identified as expressing growth-non-suppressive phenotype under strict anaerobic conditions. Sequence analysis of regions flanking the Tn insertions revealed that most of the selected mutants were defective in genes contributing to the anaerobic fumarate uptake and generation (insertions in dcuA, dcuB and aspA), or to the anaerobic L-arginine utilisation pathway (insertions in STM4467 encoding a putative arginine deiminase, and in between speF encoding ornithine decarboxylase and kdpE coding a response regulator protein). Mutants defective in flagellum synthesis (flhA) were also identified. In contrast to the in vitro results, all the mutants colonised 1-day-old chicks efficiently and suppressed the super-infection of chicks by the parent strain. This clearly indicates that neither of the metabolic pathways mentioned above nor motility play essential roles in lower intestinal tract colonisation.  相似文献   

Identification of geographic factors associated with early spread of foot-and-mouth disease     

Rivas AL  Smith SD  Sullivan PJ  Gardner B  Aparicio JP  Hoogesteijn AL  Castillo-Chávez C 《American journal of veterinary research》2003,64(12):1519-1527

OBJECTIVE: To explore whether early analysis of spatial data may result in identification of variables associated with epidemic spread of foot and mouth disease. SAMPLE POPULATION: 37 farms with infected cattle (ie, case farms) reported within the first 6 days of the 2001 Uruguayan foot-and-mouth disease epidemic. PROCEDURE: A georeferenced database was created and retrospective analysis was performed on case farm location in relation to farm density, cattle density, farm type (ie, beef vs dairy cattle production), road density, case farm distance to the nearest road, farm size, farm ownership, and day of infection. Mean or median results of 1 to 3 day versus 4 to 6 day spatial data were compared. Spatial-temporal associations were investigated by correlation analysis. RESULTS: Comparison of mean or median values between the first 3 days and days 4 to 6 of the epidemic and results of correlation analysis indicated a significant increase in road density, cattle density, and dairy cattle production and a significant decrease in farm size and case farm distance to the nearest road that developed over time. A route that linked most case farms by the shortest possible distance and also considered significantly associated variables was created. It included 86.1% of all case farms reported by 60 days into the epidemic. CONCLUSIONS AND CLINICAL RELEVANCE: Epidemic direction can be assessed on the basis of road density and other spatial variables as early as 6 days into an epidemic. Epidemic control areas may be more effectively identified if local and regional georeferenced data are considered.  相似文献   

Generalized glycogenosis in Brahman-derived breeds: diagnosis and prevalence in Argentina     

Caffaro  María Eugenia  Raschia  María Agustina  Amadio  Ariel Fernando  Poli  Mario Andrés 《Tropical animal health and production》2020,52(2):483-488

Tropical Animal Health and Production - Generalized glycogenosis is a lethal autosomal recessive disease caused by a deficient activity of the acidic 1,4-α-glucosidase enzyme and characterized...  相似文献   

Fluorine‐18 fluorodeoxyglucose positron emission tomography imaging exhibits increased SUVmax at the level of the spinal intumescence in normal dogs     

John M. French  Ariel Brody  Devin von Stade  Chad B. Frank  Lynn R. Griffin 《Veterinary radiology & ultrasound》2020,61(3):364-369

Positron emission tomography (PET) imaging utilizing fluorine‐18 labeled fluorodeoxyglucose is a relatively new imaging modality in veterinary medicine that is becoming more common for oncological staging and for musculoskeletal imaging. Thus, it is important to identify the normal variations on PET imaging that may be mistaken for pathology. Variation in standardized uptake values (SUVmax) have been anecdotally identified in the spinal cord of dogs undergoing fluorodeoxyglucose (FDG) PET–CT examinations for oncological staging, with notable increase in SUVmax values identified in the region of the cervical and lumbar spinal intumescences. The aim of this retrospective, analytical study was to compare the SUVmax values at four different locations throughout the spinal cord (C3, C5‐T1, T13, and L3‐S1) of a group of dogs with no evidence of neurologic disease and compare those findings to histologic specimens from dogs euthanized for unrelated disease. SUVmax values were significantly higher at the cervical and lumbar intumescences in comparison to the control regions (P < .0001 and P < .0001, respectively). Neuronal count and spinal cord gray matter area were also significantly greater at the cervical and lumbar intumescences (neuronal count P = .0025 and P = .0001; area P = .0004 and P = .0009, respectively) while overall neuronal density was lower (P = .003 and P = .028, respectively). We presume the increased SUVmax values at the spinal cord intumescences are the result of overall increased neuron count, increased proportion of gray matter, and increased spinal cord gray matter area. These findings will aid in the interpretation of future PET–CT studies and hopefully prevent the misdiagnosis of spinal cord disease in normal canines.  相似文献   

Pilot evaluation of a three dimensional-printed oropharyngeal airway device for brachycephalic dogs     

Pablo Nejamkin  Joaquin Araos  Ariel Genaro  Manuel Martin-Flores 《Veterinary anaesthesia and analgesia》2021,48(3):478-479

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Saproxylic species are linked to the amount and isolation of dead wood across spatial scales in a beech forest     

Haeler  Elena  Bergamini  Ariel  Blaser  Stefan  Ginzler  Christian  Hindenlang  Karin  Keller  Christine  Kiebacher  Thomas  Kormann  Urs G.  Scheidegger  Christoph  Schmidt  Ronald  Stillhard  Jonas  Szallies  Alexander  Pellissier  Loïc  Lachat  Thibault 《Landscape Ecology》2021,36(1):89-104

Context

Dead wood is a key habitat for saproxylic species, which are often used as indicators of habitat quality in forests. Understanding how the amount and spatial distribution of dead wood in the landscape affects saproxylic communities is therefore important for maintaining high forest biodiversity.

Objectives

We investigated effects of the amount and isolation of dead wood on the alpha and beta diversity of four saproxylic species groups, with a focus on how the spatial scale influences results.

Methods

We inventoried saproxylic beetles, wood-inhabiting fungi, and epixylic bryophytes and lichens on 62 plots in the Sihlwald forest reserve in Switzerland. We used GLMs to relate plot-level species richness to dead wood amount and isolation on spatial scales of 20–200 m radius. Further, we used GDMs to determine how dead wood amount and isolation affected beta diversity.

Results

A larger amount of dead wood increased beetle richness on all spatial scales, while isolation had no effect. For fungi, bryophytes and lichens this was only true on small spatial scales. On larger scales of our study, dead wood amount had no effect, while greater isolation decreased species richness. Further, we found no strong consistent patterns explaining beta diversity.

Conclusions

Our multi-taxon study shows that habitat amount and isolation can strongly differ in the spatial scale on which they influence local species richness. To generally support the species richness of different saproxylic groups, dead wood must primarily be available in large amounts but should also be evenly distributed because negative effects of isolation already showed at scales under 100 m.

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Temperature, the GacS/GacA system, and host metabolites regulate the type VI secretion system of Pseudomonas syringae pv. phaseolicola     

Jackeline Lizzeta Arvizu-Gómez  Alejandro Hernández-Morales  Alba E. Jofre-Garfias  Ariel Álvarez-Morales 《Journal of General Plant Pathology》2013,79(3):194-197

The recently discovered type VI secretion system (T6SS) is implicated in the pathogenic and/or virulence processes of diverse bacteria. The expression pattern of the T6SS differs among different organisms and also depends on several environmental factors. We initiated a study of the conditions that influence T6SS gene expression in Pseudomonas syringae pv. phaseolicola NPS3121. Our results indicate that low temperatures and plant extracts impact the expression of T6SS genes and that the process is subject to regulation by the GacS/GacA two-component system.  相似文献   

Phylogenetic Variation of Chelonid Alphaherpesvirus 5 (ChHV5) in Populations of Green Turtles Chelonia mydas along the Queensland Coast,Australia     

E. Ariel  F. Nainu  K. Jones  K. Juntunen  I. Bell  J. Gaston 《Journal of aquatic animal health》2013,25(3):150-157

Abstract

Sea turtle fibropapillomatosis (FP) is a disease marked by the proliferation of benign but debilitating cutaneous and occasional visceral tumors, likely to be caused by chelonid alphaherpesvirus 5 (ChHV5). This study presents a phylogeny of ChHV5 strains found on the east coast of Queensland, Australia, and a validation for previously unused primers. Two different primer sets (gB-1534 and gB-813) were designed to target a region including part of the UL27 glycoprotein B (gB) gene and part of UL28 of ChHV5. Sequences obtained from FP tumors found on juvenile green turtles Chelonia mydas (<65 cm curved carapace length) had substantial homology with published ChHV5 sequences, while a skin biopsy from a turtle without FP failed to react in the PCRs used in this study. The resulting sequences were used to generate a neighbor-joining tree from which three clusters of ChHV5 from Australian waters were identified: north Australian, north Queensland, and Queensland clusters. The clusters reflect the collection sites on the east coast of Queensland with a definitive north–south trend.

Received October 22, 2016; accepted May 7, 2017 Published online July 26, 2017  相似文献   

A whiff of oxygen before the great oxidation event?   总被引：1，自引：0，他引：1  

Anbar AD  Duan Y  Lyons TW  Arnold GL  Kendall B  Creaser RA  Kaufman AJ  Gordon GW  Scott C  Garvin J  Buick R 《Science (New York, N.Y.)》2007,317(5846):1903-1906

High-resolution chemostratigraphy reveals an episode of enrichment of the redox-sensitive transition metals molybdenum and rhenium in the late Archean Mount McRae Shale in Western Australia. Correlations with organic carbon indicate that these metals were derived from contemporaneous seawater. Rhenium/osmium geochronology demonstrates that the enrichment is a primary sedimentary feature dating to 2501 +/- 8 million years ago (Ma). Molybdenum and rhenium were probably supplied to Archean oceans by oxidative weathering of crustal sulfide minerals. These findings point to the presence of small amounts of O2 in the environment more than 50 million years before the start of the Great Oxidation Event.  相似文献   

Direct visualization of horizontal gene transfer     

Babic A  Lindner AB  Vulic M  Stewart EJ  Radman M 《Science (New York, N.Y.)》2008,319(5869):1533-1536

Conjugation allows bacteria to acquire genes for antibiotic resistance, novel virulence attributes, and alternative metabolic pathways. Using a fluorescent protein fusion, SeqA-YFP, we have visualized this process in real time and in single cells of Escherichia coli. We found that the F pilus mediates DNA transfer at considerable cell-to-cell distances. Integration of transferred DNA by recombination occurred in up to 96% of recipients; in the remaining cells, the transferred DNA was fully degraded by the RecBCD helicase/nuclease. The acquired integrated DNA was tracked through successive replication rounds and was found to occasionally split and segregate with different chromosomes, leading to the inheritance of different gene clusters within the cell lineage. The incidence of DNA splitting corresponds to about one crossover per cell generation.  相似文献