A mathematical model of the effects of chronic carriers on the within-herd spread of contagious bovine pleuropneumonia in an African mixed crop-livestock system     

Lesnoff M  Laval G  Bonnet P  Chalvet-Monfray K  Lancelot R  Thiaucourt F 《Preventive veterinary medicine》2004,62(2):101-117

Contagious bovine pleuropneumonia (CBPP) is a respiratory disease of cattle; CBPP is caused by Mycoplasma mycoides subsp. mycoides small colony. CBPP is a major cause for concern for African countries (because of mortality, animal-production losses and cost of control). The clinical form of the disease is the more infectious (contagion occurs essentially through coughing). However, chronic lung lesions with viable mycoplasmas can persist in recovering cattle. Animals presenting these lesions might have a time-delimitated infectious phase. Such carriers are suspected to generate field outbreaks (although this hypothesis remains debated). We investigated the potential quantitative effects of these chronic carriers on the within-herd CBPP spread. Data were collected during a longitudinal field herd survey in a mixed crop-livestock system in the Ethiopian highlands. Two stochastic Markov-chain models' outputs (seroconversion dynamics, basic reproduction ratio R0, cumulative clinical incidence and risk of herd infection) were compared given different hypotheses on the carrier infectiousness. The late seroconversions observed in the field data were fitted correctly only for the highest carrier infectiousness we considered (mean chronic duration of 1 year and carriers 50-times less infectious than clinical cases). Although sensitivities (in terms of disease impact in the herd) were in general negligible when the carrier infectiousness was low (e.g. when carriers were assumed to be 1000-times less infectious than clinical cases), they rapidly became important when the infectiousness increased.  相似文献   

Whole body barometric plethysmography: a screening method to investigate airway reactivity and acute lung injuries in freely moving pigs     

Halloy DJ  Kirschvink NA  Vincke GL  Hamoir JN  Delvaux FH  Gustin PG 《Veterinary journal (London, England : 1997)》2004,168(3):276-284

The aim of this work was to investigate whether the Penh index, measured using whole body barometric plethysmography, can be used as a screening parameter to evaluate the airway reactivity and the intensity of the pulmonary response to endotoxins. Penh was firstly recorded in non-sedated freely moving piglets exposed (1) to a nebulized acetylcholine (Ach) pre-treated or not with clenbuterol, or (2) to endotoxin challenge. To measure Penh simultaneously with total pulmonary resistance (R(L)), dynamic compliance (C(dyn)) and intrapleural pressure changes (Max Delta Ppl), an oesophageal balloon catheter technique was used and the piglets were anaesthetised. The recordings were performed during (1) an intravenous metacholine (Mch) challenge and (2) in endotoxin-exposed animals. In freely moving animals, Ach induced a significant dose-dependent increase in Penh, which was significantly blocked by clenbuterol. Endotoxin instillation also resulted in a significant rise in Penh while the corresponding response measured under anaesthesia was significantly and positively correlated with R(L) and Max Delta Ppl. Similar results were obtained during Mch challenge but the Penh was negatively correlated with C(dyn). We conclude that Penh could be used in freely moving piglets as a screening index for airway reactivity and pulmonary functional changes in cholinergic and endotoxin challenges.  相似文献   

Characterization of a New Nepovirus Infecting Apricot in Southeastern France: Apricot Latent Ringspot Virus     

Pascal Gentit  René-Pierre Delbos  Thierry Candresse  Jean Dunez 《European journal of plant pathology / European Foundation for Plant Pathology》2001,107(5):485-494

A pathogen was transmitted from apricot trees showing symptoms of viral infection to GF305 peach seedlings which reacted by stunting, shortened internodes and chlorotic mottling. The agent was transmitted to cherry, apricot, peach and plum by grafting and to several herbaceous hosts by mechanical inoculation. Isometric nepovirus-like particles of 30–31 nm diameter extracted from infected Chenopodium quinoa sedimented as two peaks in sucrose gradients. These particles contained two single stranded RNAs of approximately 5.9 and 7.9 kb, and a single coat protein subunit of 53.7 kDa. No cross-reactions were observed with a number of nepoviruses infecting fruit trees. Inoculation of purified particles to herbaceous or woody hosts reproduced the same symptoms caused by the original isolate. Sequencing of a 2.2 kbp cDNA clone covering the 3 end of the small genomic RNA identified an open reading frame encoding a 317 aa N-truncated protein exhibiting significant similarities with the coat protein of nepoviruses. The 1257 nt long 3 non-coding region showed up to about 65% homology to the equivalent region of members of the subgroup C of nepoviruses. The properties of this pathogen do not match those of any previously described nepovirus. It should therefore be considered as a new member of the subgroup C of nepoviruses, for which the name of Apricot latent ringspot virus (ALRSV) is proposed.The nucleotide sequence reported in this work has been deposited in the EMBL databank under the accession number AJ278875.  相似文献   

Usefulness of single copy genes containing introns in Phytophthora for the development of detection tools for the regulated species P. ramorum and P. fragariae     

Renaud Ioos  Lise Laugustin  Nathalie Schenck  Sylvie Rose  Claude Husson  Pascal Frey 《European journal of plant pathology / European Foundation for Plant Pathology》2006,116(2):171-176

Introns are generally highly polymorphic regions within genes and were proven to be of great interest for discriminating among phylogenetically-close Phytophthora species. Phytophthora ramorum and P. fragariae are considered as quarantine pathogens by the European Union and accurate detection tools are therefore necessary for their monitoring. From introns located in different single copy genes (GPA1, RAS-like, and TRP1), we developed a series of PCR primers specific to P. ramorum and P. fragariae. The specificity of these primers was successfully checked with a wide collection of Phytophthora isolates and a protocol was developed to detect both pathogens directly in infected plant tissues. These genes should be of particular interest for the development of additional species-specific detection tools within the Phytophthora genus.  相似文献   

Glossopharyngeal Insufflation and Breath-Hold Diving: The More,the Worse?     

Alain Boussuges  Olivier Gavarry  Jacques Bessereau  Mathieu Coulange  Morgan Bourc’his  Pascal Rossi 《The Forestry Chronicle》2014,25(4):466-471

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Misconduct annotations     

Pascal CB 《Science (New York, N.Y.)》1996,274(5290):1066b-1067b

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Early Archaean microorganisms preferred elemental sulfur, not sulfate     

Philippot P  Van Zuilen M  Lepot K  Thomazo C  Farquhar J  Van Kranendonk MJ 《Science (New York, N.Y.)》2007,317(5844):1534-1537

Microscopic sulfides with low 34S/32S ratios in marine sulfate deposits from the 3490-million-year old Dresser Formation, Australia, have been interpreted as evidence for the presence of early sulfate-reducing organisms on Earth. We show that these microscopic sulfides have a mass-independently fractionated sulfur isotopic anomaly (Delta33S) that differs from that of their host sulfate (barite). These microscopic sulfides could not have been produced by sulfate-reducing microbes, nor by abiologic processes that involve reduction of sulfate. Instead, we interpret the combined negative delta34S and positive Delta33S signature of these microscopic sulfides as evidence for the early existence of organisms that disproportionate elemental sulfur.  相似文献   

不同水基防腐剂处理木材的表面自由能   总被引：4，自引：0，他引：4  

曹金珍 《北京林业大学学报》2006,28(4):1-5

该研究中测定了蒸馏水、二碘甲烷、甲酰胺和甘油等4种参照液体在不同水基防腐处理（包括铬化砷酸铜CCA以及另外两种商品名为NW和NS的处理）后的木材表面所形成的接触角，并根据酸碱作用理论计算得到其表面自由能及其两个分量——Lifshiz van der Waals（LW）分量和酸碱作用（AB）分量.结果表明，NW和CCA处理使木材表面的疏水性有所增加，而NS处理由于早材的水分渗透速率加快总体表现为亲水性增加.利用蒸馏水、二碘甲烷、甲酰胺这3种参照液体计算得到的未处理早材、未处理晚材、CCA处理早材、CCA处理晚材、NW处理早材、NW处理晚材、NS处理早材和NS处理晚材的表面自由能分别为43.1、44.5、43.4、45.1、49.4、40.6、46.0和40.9 mJ/m[[sup]]2[[/sup]].由此可见，CCA处理材的表面自由能接近于未处理材，而经过NW和NS处理后，早材和晚材的表面能都有一定程度的变化，但对于木材整体来说表面自由能仍接近于未处理材.   相似文献   

High-quality binary protein interaction map of the yeast interactome network   总被引：1，自引：0，他引：1  

Yu H  Braun P  Yildirim MA  Lemmens I  Venkatesan K  Sahalie J  Hirozane-Kishikawa T  Gebreab F  Li N  Simonis N  Hao T  Rual JF  Dricot A  Vazquez A  Murray RR  Simon C  Tardivo L  Tam S  Svrzikapa N  Fan C  de Smet AS  Motyl A  Hudson ME  Park J  Xin X  Cusick ME  Moore T  Boone C  Snyder M  Roth FP  Barabási AL  Tavernier J  Hill DE  Vidal M 《Science (New York, N.Y.)》2008,322(5898):104-110

Current yeast interactome network maps contain several hundred molecular complexes with limited and somewhat controversial representation of direct binary interactions. We carried out a comparative quality assessment of current yeast interactome data sets, demonstrating that high-throughput yeast two-hybrid (Y2H) screening provides high-quality binary interaction information. Because a large fraction of the yeast binary interactome remains to be mapped, we developed an empirically controlled mapping framework to produce a "second-generation" high-quality, high-throughput Y2H data set covering approximately 20% of all yeast binary interactions. Both Y2H and affinity purification followed by mass spectrometry (AP/MS) data are of equally high quality but of a fundamentally different and complementary nature, resulting in networks with different topological and biological properties. Compared to co-complex interactome models, this binary map is enriched for transient signaling interactions and intercomplex connections with a highly significant clustering between essential proteins. Rather than correlating with essentiality, protein connectivity correlates with genetic pleiotropy.  相似文献   

Suppression of microRNA-silencing pathway by HIV-1 during virus replication   总被引：1，自引：0，他引：1  

Triboulet R  Mari B  Lin YL  Chable-Bessia C  Bennasser Y  Lebrigand K  Cardinaud B  Maurin T  Barbry P  Baillat V  Reynes J  Corbeau P  Jeang KT  Benkirane M 《Science (New York, N.Y.)》2007,315(5818):1579-1582

MicroRNAs (miRNAs) are single-stranded noncoding RNAs of 19 to 25 nucleotides that function as gene regulators and as a host cell defense against both RNA and DNA viruses. We provide evidence for a physiological role of the miRNA-silencing machinery in controlling HIV-1 replication. Type III RNAses Dicer and Drosha, responsible for miRNA processing, inhibited virus replication both in peripheral blood mononuclear cells from HIV-1-infected donors and in latently infected cells. In turn, HIV-1 actively suppressed the expression of the polycistronic miRNA cluster miR-17/92. This suppression was found to be required for efficient viral replication and was dependent on the histone acetyltransferase Tat cofactor PCAF. Our results highlight the involvement of the miRNA-silencing pathway in HIV-1 replication and latency.  相似文献