Providing management options to control corn mouse (Calomys musculinus) reservoir populations using a cohort structured model

We evaluate several management options for Calomys musculinus populations through the formulation and validation of a cohort structured model. Initially, a basic model was constructed and validated using field population data. Next, the model was altered to allow us to evaluate different management options. In general, basic model results were in agreement with field data, demonstrating that this model would be useful in describing aspects of corn mouse population dynamics. Restricting control measures to when mouse numbers reach high levels would be inadequate, because population numbers tend to increase in size after some years. In contrast, reducing vegetation cover in spring was more effective in reducing field population abundances. Despite some limitations, the model could be useful for evaluating the relationships between population dynamics and some biotic or physical environmental variables, and thus ensure more efficient use of resources in integrated pest management.     

Differentially-regulated defence genes in Malus domestica during phytoplasma infection and recovery

To improve knowledge about plant/phytoplasma interactions and, in particular, about the ‘recovery’ phenomenon in previously-infected plants, we investigated and compared expression levels of several defence-related genes (four pathogenesis-related proteins and three jasmonate-pathway marker enzymes) in apple plants showing different states of health: vigorous (healthy), phytoplasma-infected, and recovered. Real Time-PCR analyses demonstrated that genes are differentially expressed in apple leaf tissue according to the plants’ state of health. Malus domestica Pathogenesis-Related protein (MdPR) 1, MdPR 2 and MdPR 5 were significantly induced in leaves of diseased and symptomatic plants compared to leaves of those plants that were healthy or recovered. On the other hand, levels of all the jasmonate (JA)-pathway marker genes that we selected for this study, were up-regulated in the leaves of recovered plants compared to the diseased ones. In conclusion, our study demonstrated that two different sets of defence genes are involved in the interactions between apple plants and ‘Candidatus Phytoplasma mali’ (‘Ca. P. mali’) and that these genes are differentially expressed during phytoplasma infection or recovery.     

Spontaneous pneumopericardium in a dog with bronchopulmonary disease complicated by pyothorax and pneumothorax

Spontaneous pneumopericardium is a rare condition consisting of pericardial gas in the absence of iatrogenic or traumatic causes; it has been described secondary to pneumonia, lung abscess, and bronchopulmonary disease. This report describes a case of spontaneous pneumopericardium in a dog presenting with dyspnea secondary to pyopneumothorax complicating a bronchopulmonary disease.     

Strategies for reduced antibiotic usage in dairy cattle farms

The need for antibiotic treatments in dairy cattle farms can be reduced by a combined intervention scheme based on: (1) timely clinical inspections, (2) the assessment of animal-based welfare parameters, and (3) the use of predictive laboratory tests. These can provide greater insight into environmental adaptation of dairy cows and define animals at risk of contracting disease. In the long-term, an improved disease control justifies the adoption of such a combined strategy. Many antibiotic treatments for chronic disease cases are often not justified with a cost/benefit analysis, because the repeated drug administration does not give rise to the expected outcome in terms of animal health. In particular, compared with untreated cases, antibiotics may not lead to greater cure rates for some forms of mastitis. Lastly, a substantial reduction of antibiotic usage in dairy farms can be achieved through the proper use of immunomodulators, aimed at increasing immunocompetence and disease resistance of cows.     

Multi-event capture–recapture modeling of host–pathogen dynamics among European rabbit populations exposed to myxoma and Rabbit Hemorrhagic Disease Viruses: common and heterogeneous patterns

Host–pathogen epidemiological processes are often unclear due both to their complexity and over-simplistic approaches used to quantify them. We applied a multi-event capture–recapture procedure on two years of data from three rabbit populations to test hypotheses about the effects on survival of, and the dynamics of host immunity to, both myxoma virus and Rabbit Hemorrhagic Disease Virus (MV and RHDV). Although the populations shared the same climatic and management conditions, MV and RHDV dynamics varied greatly among them; MV and RHDV seroprevalences were positively related to density in one population, but RHDV seroprevalence was negatively related to density in another. In addition, (i) juvenile survival was most often negatively related to seropositivity, (ii) RHDV seropositives never had considerably higher survival, and (iii) seroconversion to seropositivity was more likely than the reverse. We suggest seropositivity affects survival depending on trade-offs among antibody protection, immunosuppression and virus lethality. Negative effects of seropositivity might be greater on juveniles due to their immature immune system. Also, while RHDV directly affects survival through the hemorrhagic syndrome, MV lack of direct lethal effects means that interactions influencing survival are likely to be more complex. Multi-event modeling allowed us to quantify patterns of host–pathogen dynamics otherwise difficult to discern. Such an approach offers a promising tool to shed light on causative mechanisms.     

Degradation of scrapie associated prion protein (PrPSc) by the gastrointestinal microbiota of cattle

A food-borne origin of the transmission of bovine spongiform encephalopathy (BSE) to cattle is commonly assumed. However, the fate of infectious prion protein during polygastric digestion remains unclear. It is unknown at present, whether infectious prion proteins, considered to be very stable, are degraded or inactivated by microbial processes in the gastrointestinal tract of cattle. In this study, rumen and colon contents from healthy cattle, taken immediately after slaughter, were used to assess the ability of these microbial consortia to degrade PrP(Sc). Therefore, the consortia were incubated with brain homogenates of scrapie (strain 263K) infected hamsters under physiological anaerobic conditions at 37 degrees C. Within 20 h, PrP(Sc) was digested both with ruminal and colonic microbiota up to immunochemically undetectable levels. Especially polymyxin resistant (mainly gram-positive) bacteria expressed PrP(Sc) degrading activity. These data demonstrate the ability of bovine gastrointestinal microbiota to degrade PrP(Sc) during digestion.     

Metal contamination effects on sunflower (Helianthus annuus L.) growth and protein expression in leaves during development

Metal-ion contamination (Cd, Cu, Pb, and Zn) on sunflower (Helianthus annuus L.) growth and total leaf protein expression were studied in the present work. The height, mass production, and metal distribution (Ca, K, Fe, Mg, Na, and P) in all plant fractions (roots, stems, and leaves) were evaluated. Sunflowers plants contaminated with four metal ions decreases height and mass by 35% and 40%, respectively, compared to control. Significant differences of total protein composition were noted after SDS-PAGE separation. Sunflower proteomics were more affected when 500 mg L(-1) of metal ion was added as contaminant of both zinc and mixed ions solution. In these cases, proteins having a molar mass of 14.5, 34.5, and 54.0 kDa were present at a lower level and alterations in enzymatic activities (SOD and GR) were found. Sunflowers plants contaminated with zinc and the mixed ions solution showed some degree of oxidative stress.     

Curcuminoids form reactive glucuronides in vitro

Curcumin is of current interest because of its putative anti-inflammatory, anticarcinogenic, and anti-Alzheimer's activity, but its pharmacokinetic and metabolic fate is poorly understood. The present in vitro study has therefore been conducted on the glucuronidation of curcumin and its major phase I metabolite, hexahydro-curcumin, as well as of various natural and artificial analogs. The predominant glucuronide generated by rat and human liver microsomes from curcumin, hexahydro-curcumin, and other analogs with a phenolic hydroxyl group was a phenolic glucuronide according to LC-MS/MS analysis. However, a second glucuronide carrying the glucuronic acid moiety at the alcoholic hydroxyl group was formed from the same curcuminoids, but not hexahydro-curcuminoids, by human microsomes. Curcuminoids without a phenolic hydroxyl group gave rise to the aliphatic glucuronide only. The phenolic glucuronides of curcuminoids, but not of hexahydro-curcuminoids, were rather lipophilic and, in part, unstable in aqueous solution, their stability depending strongly on the type of aromatic substitution. The phenolic glucuronide of curcumin and of its natural congeners, but not the parent compounds, clearly inhibited the assembly of microtubule proteins under cell-free conditions, implying chemical reactivity of the glucuronides. These novel properties of the major phase II metabolites of curcuminoids deserve further investigation.     

Genetic variability of the prion protein gene (PRNP) in wild ruminants from Italy and Scotland

The genetics of the prion protein gene (PRNP) play a crucial role in determining the relative susceptibility to transmissible spongiform encephalopathies (TSEs) in several mammalian species. To determine the PRNP gene variability in European red deer (Cervus elaphus), roe deer (Capreolus capreolus) and chamois (Rupicapra rupicapra), the PRNP open reading frame from 715 samples was analysed to reveal a total of ten single nucleotide polymorphisms (SNPs). In red deer, SNPs were found in codons 15, 21, 59, 78, 79, 98, 136, 168 and 226. These polymorphisms give rise to 12 haplotypes, and one of which is identical to the PRNP of American wapiti (Rocky Mountain elk, Cervus elaphus nelsoni). One silent mutation at codon 119 was detected in chamois and no SNPs were found in roe deer. This analysis confirmed that European wild ruminants have a PRNP genetic background that is compatible with TSE susceptibility, including chronic wasting disease.     

Distribution and frequency of VKORC1 sequence variants conferring resistance to anticoagulants in Mus musculus

BACKGROUND: Emerging resistance to anticoagulant rodenticides may significantly impair house mouse (Mus musculus L.) control. As in humans and rats, sequence variants in the gene vitamin K epoxide reductase complex subunit 1 (VKORC1) of house mice are strongly implicated in the responses of mice to anticoagulants. This study gives a first overview of the distribution and frequency of such potentially resistance‐conferring sequence variants in house mice, based on tissue samples from 30 populations in Germany, Switzerland and the Azores. RESULTS: Except for one population from south Germany, sequence variants were found in individuals from all locations sampled (29 out of 30 sites surveyed), with less than 10% of the individuals matching the wild‐type genotype. The most frequent and widespread amino acid substitutions were Leu128Ser, Tyr139Cys and a group of linked sequence changes (Arg12Trp/Ala26Ser/Ala48Thr/Arg61Leu). Where these substitutions occurred as the sole variant, the proportion of homozygous individuals was 72–83%. CONCLUSIONS: An evaluation of published data revealed that the three most frequently found sequence variants are associated with a substantial loss of rodenticide efficacy of first‐generation anticoagulants (e.g. warfarin, coumatetralyl), as well as the second‐generation compound bromadiolone and most probably also difenacoum. Knowledge of the distribution and frequency of resistance‐conferring sequence variants will stimulate their further functional characterisation and facilitate the choice of effective active substances for house mouse control. Copyright © 2011 Society of Chemical Industry