Characterization of the immune response of domestic fowl following immunization with proteins extracted from Dermanyssus gallinae

Dermanyssus gallinae is the most significant ectoparasite of European poultry egg laying production systems due to high costs of control and associated production losses as well as adverse effects on bird welfare. In this study, soluble proteins were extracted from unfed D. gallinae (DGE) using a urea-based detergent and ultra-filtration, passed through a 0.22 μm filter and blended aseptically with adjuvant. One group of laying hens was immunized with DGE and adjuvant (Montanide ISA 50 V) whilst another group (Control) received physiological saline and adjuvant. All birds were immunized on two occasions, 21 days apart. Antibody response to immunization was determined by ELISA and western blotting using immunoglobulins (Igs) extracted from egg yolk. DGE immunization of hens resulted in a significant (P < 0.05) IgY response compared to controls, although there was no significant difference in IgM response between treatments. A number of proteins were identified by western blotting using IgY antibodies from DGE immunized birds, most prominently at 40 and 230 kDa. Analysis of proteins from approximately corresponding bands on SDS-PAGE confirmed the identity of tropomyosin, whilst other proteins showed high sequence homology with myosin and actin from other arachnid and insect species. Immunization of hens with DGE resulted in a 50.6% increase in mite mortality (P < 0.001) 17 h after feeding when tested by an in vitro mite feeding model. Data in this study demonstrate that somatic antigens from D. gallinae can be used to stimulate a protective immune response in laying hens. Further work is needed to identify other proteins of interest that could confer higher protection against D. gallinae, as well as optimization of the vaccination and in vitro testing protocol.     

Forests planted for ecosystem restoration or conservation

Although the phrase, planting for ecosystem restoration, is of recent origin, many of the earliest large-scale tree plantings were made for what we now refer to as restoration or conservation goals. Forest restoration activities may be needed when ecosystems are disturbed by either natural or anthropogenic forces. Disturbances can impact (1) basic components of the system (e.g., plant and animal composition, soil pools, and atmospheric pools), (2) ecosystem processes, i.e., interactions among basic components, or (3) both components and processes. Early efforts at restoration or site rehabilitation focused primarily on reducing off-site impacts, such as sediment introduced into streams from ecosystems that had been severely disturbed. More recent restoration programs include ecosystems in which only some of the components are missing or some of the processes have been impacted. Restoration activities can begin immediately after the disturbance has ended. Although forest restoration projects can include many activities, planting is almost always a key component.When planning an ecosystem restoration project, land managers need to be aware that commonly used plant establishment and management procedures may need to be altered to meet project objectives. Some systems may have been so severely impacted that ameliorative activities, e.g., fertilization, liming, land contouring, and microsite preparation, will be necessary prior to planting. Managers may also need to take special measures to reduce herbivory, control competing vegetation, or reduce physical damage from wind or sun. Choice of species needs careful consideration. Desired species may not grow well on degraded sites, may need a nurse species to become established, or may not provide an opportunity to harvest a short-term crop to reduce restoration costs. New methods may need to be developed for projects that require underplanting or interplanting. The end result of restoration should be an ecosystem with the same level of heterogeneity inherent in an undisturbed system; thus, managers should consider how pre- and postplanting activities will affect system variability.As our understanding of ecosystems has increased, so has our expectation that restored ecosystems have the same components and function in the same manner as do undisturbed systems. These expectations require that land managers have more sophisticated information than was considered necessary previously. In the absence of more pertinent information, we can prescribe restoration activities based on results from related ecosystems or on theoretical considerations. Additional research, careful monitoring, and adaptive management are critical to our long-term success.     

Salmonella and Erysipelothrix infection in swine: a laboratory summary.

The occurrence of salmonellas and Erysipelothrix rhusiopathiae in tissues of swine was determined by bacteriologic and fluorscent antibody examination of 5,297 specimens from herds investigated for hog cholera. Of the specimens examined, 35.5% were positive for salmonellas, 21.1% were positive for E rhusiopathiae, and 8.3% were positive for both salmonellas and E rhusiopathiae.     

Antimicrobial activity of gallium against virulent Rhodococcus equiin vitro and in vivo

Rhodococcus equi, a facultative intracellular bacterium, causes severe pneumonia in foals. Evidence suggests that most foals become infected very early in life, when they have immature or ineffective innate immune responses. This study evaluated the antimicrobial activity of gallium against R. equi, as a potential chemoprophylactic and therapeutic agent. Rhodococcus equi was grown in media with various concentrations of gallium nitrate (GN), with and without excess iron. GN significantly inhibited growth and killed R. equi, and these effects were abolished with excess iron. Antimicrobial effects of Ga appear to be related to its interference with iron metabolism. Mice were treated orally with gallium maltolate (GaM), 10 or 50 mg/kg BW, or distilled H2O prior to and after experimental infection with R. equi. Six days post-infection, organs were harvested and R. equi concentrations assessed, and serum gallium concentrations determined. GaM was absorbed in a dose-dependent manner, and R. equi tissue burdens were greater in control mice than in all GaM-treated mice. GaM may aid in the control of disease by preventing development of overwhelming R. equi tissue burdens prior to the establishment of requisite innate and adaptive immune responses.     

Effects of iron modulation on growth and viability of Rhodococcus equi and expression of virulence-associated protein A

OBJECTIVE: To determine the importance of iron for in vitro growth of Rhodococcus equi, define potential iron sources in the environment and mechanisms by which R equi may obtain iron from the environment, and assess expression and immunogenicity of iron-regulated proteins. SAMPLE POPULATION: 10 virulent and 11 avirulent strains of R equi. PROCEDURE: In vitro growth rates and protein patterns of R equi propagated in media with normal, excess, or limited amounts of available iron were compared. Immunoblot analyses that used serum from foals naturally infected with R equi and monoclonal antibody against virulence-associated protein (Vap)A were conducted to determine immunogenicity and identity of expressed proteins. RESULTS: Excess iron did not alter growth of any R equi strains, whereas growth of all strains was significantly decreased in response to limited amounts of available iron. Virulent R equi were able to use iron from ferrated deferoxamine, bovine transferrin, and bovine lactoferrin. Only virulent R equi expressed an iron-regulated, immunogenic, surface-associated protein identified as VapA. CONCLUSIONS AND CLINICAL RELEVANCE: Iron is required for the growth and survival of R equi. Sources of iron for R equi, and mechanisms by which R equi acquire iron in vivo, may represent important virulence factors and novel targets for the development of therapeutic and immunoprophylactic strategies to control R equi infection in foals. Expression of VapA is substantially upregulated when there is a limited amount of available iron.     

A XERORADIOGRAPHIC STUDY OF THE DEVELOPING EQUINE FOREDIGIT AND METACARPOPHALANGEAL REGION FROM BIRTH TO SIX MONTHS OF AGE

The purpose of the project was to provide a reference for radiographic anatomy of the developing equine foredigit and metacarpophalangeal region. Using xeroradiographic techniques, both foredigits and meta-carpophalangeal regions of six Quarter Horse foals were radiographed at one day of age and at two-week intervals until the foals were six weeks old. The foals were then radiographed at four-week intervals until they were 12 months old. This report deals specifically with the first six months of postnatal development. Lateromedial and dorsopalmar xeroradiographs of each foredigit and metacarpophalangeal region and a dorsal 65° proximal-palmarodistal oblique view of the distal part of the digit were made for each examination. The foals were weighed and measured at the withers immediately prior to each examination. Representative xeroradiographs were selected and appropriately labeled to demonstrate normal radio-graphic anatomy of these regions. First radiographic appearance of distal epiphyseal ossification in metacarpal 2 and metacarpal 4 was extremely variable and ranged from four to 38 weeks. Radiographic closure of the proximal physis of the middle phalanx ranged from 18 to 30 weeks (mean = 26 weeks). Radiographic closure of the proximal physis of the proximal phalanx ranged from 22 to 38 weeks (mean = 30 weeks). Radiographic closure of the distal physis of metacarpal 3 ranged from 18 to 38 weeks (mean = 29 weeks). When xeroradiographic physeal closure times were compared with scintigraphic closure times from a companion study, results correlated very well. A crena marginis solearis was observed in ten of 12 forelimbs (83.3%); its first radiographic appearance ranged from four to 22 weeks (mean = 11–12 weeks). A consistent groove in the hoof wall, which formed near the time of birth and moved distally at about 3 mm per week, was noted. The groove's distance from the proximal hoof border may be useful in age estimation of foals less than 18–20 weeks old.