Pathologic and immunohistochemical findings in an outbreak of systemic toxoplasmosis in a mob of red kangaroos

Toxoplasma gondii is a zoonotic protozoan pathogen that infects many endothermic vertebrates, including humans; the domestic cat and other felids serve as the definitive host. Macropodids are considered highly susceptible to toxoplasmosis. Here, we describe the clinical, pathologic, and immunohistochemical findings of an outbreak of systemic toxoplasmosis in a mob of 11 red kangaroos (Macropus rufus), with high morbidity (73%) and mortality (100%) rates. Affected animals had either severe and rapidly deteriorating clinical conditions or sudden death, which was correlated with widespread necrotizing lesions in multiple organs and intralesional T. gondii organisms identified via MIC3-specific immunohistochemistry and confirmed by REP529-specific rtPCR. Quantification of parasites demonstrated the highest parasite density in pulmonary parenchyma compared with other tissues. Our study highlights the continued importance of this severe condition in Australian marsupials.     

Describing Human–Wildlife Interaction from a European Perspective

European researchers from both the natural and social sciences show growing interest in studying interactions between society and wildlife. A wealth of theoretical frameworks, concepts, and methods are used, but an integration of perspectives is lacking. This research note summarizes results from two workshops that included 63 delegates from 25 European countries, as well as a follow-up survey of 41 respondents. Two main theoretical approaches to the study of human–wildlife interactions were identified. One approach focuses on the collective societal level relying on theories of governance, social representation, deliberative procedures, and commons theory. The other approach targets individuals or groups, and is based on theories such as the cognitive hierarchy, theory of reasoned action, and theory of planned behavior. Interdisciplinary collaboration is needed to identify the best options for wildlife conservation and management in a more politically integrated Europe.     

Influence of water potential on nitrification and structure of nitrifying bacterial communities in semiarid soils

The objective of this study was to examine the relationship between soil water potential, nitrifier community structure and nitrification activity in semiarid soils. Soils were collected after a 5-month dry period (end of summer) and subsequently rewetted to specific water potentials and incubated for 7 days prior to analysis of nitrification activity and nitrifier community structure. The approach used in this study targeted a 491bp segment of the amoA gene which encodes the active site of the ammonia monooxygenase enzyme, which is the key enzyme for all aerobic ammonia oxidisers. amoA serves as a useful target for environmental studies since it is both specific and universal for all ammonia oxidisers and reflects the phylogeny of the ammonia oxidisers. Our results suggest that in semiarid soils water potential plays a key role in determining the structure of ammonia oxidising bacteria (AOB), and that additionally AOB community structure is correlated to potential nitrification rate in these soils.     

芳香植物精油对竹子根际微生物种群的影响

竹林生态系统虽然比较稳定,但病原菌也较多,使用生物农药是竹林可持续发展的必然道路。许多芳香植物精油具有优良的抗菌活性,都有作为生物农药的潜力。但是竹林土壤微生物也可能受到精油抑菌性能的影响。本研究选取常见5种芳香植物精油香茅、肉桂、大蒜、生姜和茶树精油,对其化学成分进行鉴定并对毛竹实生盆栽苗的土壤进行处理,测定毛竹根际土壤微生物的细菌丰度和种群多样性。结果表明,5种精油会降低毛竹根际微生物的丰度和多样性,使变形菌门的细菌成为绝对优势菌群。对微生物的影响从大到小依次是香茅、生姜、茶树、肉桂和大蒜精油。     

Frequency of superantigen-producing Staphylococcus intermedius isolates from canine pyoderma and proliferation-inducing potential of superantigens in dogs

This preliminary study investigated the potential role of staphylococcal superantigens in the pathogenesis of canine pyoderma. The staphylococcal enterotoxins A (SEA), SEB, SEC and SED, and the toxic shock syndrome toxin-1 (TSST-1) were assayed in isolates from skins of dogs with pyoderma. Culture supernatants from 25 of 96 isolates were positive for multiple superantigens, with SEA and SEC being the most frequently detected. In in vitro stimulation of canine peripheral blood mononuclear cells and quantitative flow cytometry revealed that low concentrations of SEA and SEB were potent stimulators of blastogenesis of T cells.     

Influence of a probiotic Enterococcus faecium strain on selected bacterial groups in the small intestine of growing turkey poults.

A feeding trial was carried out with turkey poults, which were fed a diet containing 10(10) viable probiotic E. faecium NCIB 10415 cells/kg feed. Samples of the intestinal tract were analyzed for lactate, colony forming units of total anaerobic bacteria, lactic acid bacteria, enterobacteria and enterococci. Furthermore, metabolic activity of total eubacterial, lactobacilli and enterococci was recorded in selected RNA-extracts with specific ribosomal RNA oligonucleotide probes. Animals fed the probiotic diet showed continously increasing lactate concentrations throughout the sampling period up to day 42 of life. No correlation was found for colony forming units (cfu) of lactic acid bacteria, but metabolic activity of lactobacilli showed very close relation to continously increasing lactate concentrations. Throughout the feeding trial, enterococci in the control group continously increased to a maximum of 10(4) cfu/g wet weight, but 10-fold higher enterococci cfu were generally found in the treated group. However, rRNA content as measure for metabolic activity showed a drastic decline in both groups after high metabolic activities on day 7. This study shows that E. faecium NCIB 10415 (E. faecium SF68) stimulates other lactic acid bacteria in the small intestine, especially lactobacilli.     

Aluminium precipitates from groundwater of an aquifer affected by acid atmospheric deposition in the Senne,Northern Germany

White precipitates collected from stream bottoms and well tubes in the Senne area consist of amorphous aluminium hydroxide, coprecipitated with minor amounts of sulfate, phosphate and silica. The precipitates have presumably formed by the interaction of slightly alkaline water from calcareous subsoil sediments, with acidic water draining off sandy soils affected by high inputs of acidic atmospheric deposition. From many hydrochemical studies, precipitation of aqueous aluminium is known to occur in subsurface horizons of acid soils affected by acid rain. On the basis of presumed equilibrium with soil solutions, jurbanite, AlOHSO₄ · 5H₂O, is often assumed to be the secondary mineral involved. However, direct evidence for jurbanite from solid phase analysis is lacking. This first analysis of such a secondary phase does not support the jurbanite hypothesis, and shows that amorphous Al hydroxide can be formed instead.     

A method to assess whether ‘preferential use’ occurs after N ammonium addition; implication for the N isotope dilution technique

The robustness of the assumption of equilibrium between native and added N during ¹⁵N isotope dilution has recently been questioned by Watson et al. (Soil Biol Biochem 32 (2000) 2019-2030). We re-analyzed their raw data using equations that consider the added and native NH₄⁺ and NO₃⁻ pools as separate state variables. Gross mineralization rates and first-order rate constants for NH₄⁺ and NO₃⁻ consumption were obtained by combining analytical integration of the differential equations with a non-linear fitting procedure. The first-order rate constants for NH₄⁺ consumption and NO₃⁻ immobilization for the added NH₄⁺ and NO₃⁻ pool were used to estimate gross mineralization rates and first-order rate constants for nitrification of native NH₄⁺. The latter were 2-4 times lower than the first-order rate constants derived from the added N pool. This discrepancy between first-order rate constants for nitrification implies that one or more process rates estimated for the added N pools cannot be applied to the native N pools. Preferential use of the added N resulted in an overestimation of the gross mineralization by 1.5-2.5-fold, emphasizing the need for critical evaluation of the assumption of equilibrium before gross mineralization rates are calculated.