Pathogenesis studies with Australian bat lyssavirus in grey-headed flying foxes (Pteropus poliocephalus)

OBJECTIVE: To examine the susceptibility of the grey-headed flying fox (Pteropus poliocephalus) to Australian bat lyssavirus (ABL), and to provide preliminary observations on the pathogenesis of the disease in flying foxes. PROCEDURE: Ten flying foxes were inoculated intramuscularly with ABL, and four with a bat-associated rabies virus. Inoculated animals were observed daily, and clinical samples collected every 9 to 14 days. Animals with abnormal clinical signs were euthanased, and samples collected for histological, serological, virological and immunohistological examinations. At 3 months post inoculation (PI), all survivors were euthanased, and each submitted to a similar examination. RESULTS: Three ABL-inoculated flying foxes, and two rabies-inoculated animals developed abnormal clinical signs between 15 and 24 days PI. All three ABL-inoculated animals had histological lesions consistent with a lyssavirus infection, and lyssaviral antigen was identified in the central nervous system (CNS) of each. Virus was isolated from the brain of two affected animals. Of the rabies-inoculated flying foxes, both had histological lesions and viral antigen in the CNS. Virus was recovered from the brain of only one. None of the five affected flying foxes developed anti-lyssavirus antibodies, but, by 3 months PI, five of the seven ABL-inoculated survivors, and one of the two rabies virus-inoculated survivors, had seroconverted. The dynamics of the immune responses were quite variable. CONCLUSIONS: The response of flying foxes to ABL, administered by a peripheral route of inoculation, was similar to that of bats inoculated peripherally with bat-derived rabies viruses.     

Production of insulin-like growth factor-I by granulosa cells but not thecal cells is hormonally responsive in cattle

To determine whether the hormonal regulation of IGF-I production differs between granulosa and thecal cells in cattle, granulosa and thecal cells from bovine follicles were collected, cultured for 2 d in medium containing 10% fetal calf serum, washed, and then treated for an additional 24 h in serum-free medium with various hormones. In Exp. 1, granulosa cells were treated with 0 or 100 ng/mL of insulin and(or) 50 ng/mL of follicle-stimulating hormone (FSH), insulin plus 10 ng/mL of epidermal growth factor, or insulin plus 10 ng/mL of basic fibroblast growth factor. In Exp. 2, thecal cells were treated as described in Exp. 1 except that 100 ng/mL of luteinizing hormone (LH) was used instead of 50 ng/mL of FSH. In Exp. 3, granulosa and thecal cells were treated with 0 or 30 ng/mL of cortisol with or without 100 ng/mL of insulin, 300 pg/mL of glucagon, or glucagon plus insulin. In Exp. 4, granulosa and thecal cells were treated with 0 or 300 ng/mL of estradiol with or without 100 ng/mL of insulin and(or) 100 ng/mL of LH. At the end of treatment, medium was collected, concentrated with Centricon-3 concentrators, and assayed for IGF-I by radioimmunoassay. Cell numbers were determined by Coulter counting at the end of culture. Thecal cells produced low amounts of IGFI (0.48 +/- 0.04, 0.63 +/- 0.03, and 0.82 +/- 0.03 ng per 100,000 cells per 24 h in Exp. 2, 3, and 4, respectively), and this production was not influenced (P > 0.05) by the various treatments. In contrast, IGF-I production by granulosa cells (2.0 to 6.2 ng per 100,000 cells per 24 h) was influenced by treatment in Exp. 1, 3, and 4 and was greater than IGF-I production by thecal cells (Exp. 2, 3, and 4). Alone, insulin, FSH, LH, and cortisol (but not estradiol) each decreased (P < 0.05) granulosa-cell IGF-I production by 20 to 57%; combined treatments of insulin plus FSH or insulin plus cortisol decreased IGF-I production to levels seen with insulin alone. Glucagon had no effect (P > 0.10) on IGF-I production in the absence or presence of insulin. In the presence of insulin, epidermal growth factor, basic fibroblast growth factor, and estradiol decreased (P < 0.05) IGF-I production below that observed for insulin alone. These results indicate that, during follicular development in cattle, changes in intrafollicular levels of IGF-I may be due to hormonally-induced changes in granulosa-cell, but not thecal-cell, IGF-I production.     

A non-destructive approach for assessing decay in preservative treated wood

This study investigated the suitability of the non-destructive vibration-impulse excitation technique to assess the attack of preservative-treated wood in contact with the ground. Small stakes (10×5×100 mm³) of treated and untreated Scots pine sapwood were exposed to decay in laboratory-scale terrestrial ecosystems. Different soils were used to prove the influence of different types of wood destroying micro-organisms. Wood decay was monitored periodically for one year by determining mass losses and changes in dynamic modulus of elasticity. The results show a large variability in resistance against attacking fungi, depending on wood preservative and soil type. The non-destructive approach using the dynamic modulus of elasticity proved to be a good and sensitive tool for assessing the attack of stakes in laboratory soil testing.     

Production of Wild Buffalo (Bubalus arnee) Embryos by Interspecies Somatic Cell Nuclear Transfer Using Domestic Buffalo (Bubalus bubalis) Oocytes

The objective of this study was to explore the possibility of producing wild buffalo embryos by interspecies somatic cell nuclear transfer (iSCNT) through handmade cloning using wild buffalo somatic cells and domestic buffalo (Bubalus bubalis) oocytes. Somatic cells derived from the ear skin of wild buffalo were found to express vimentin but not keratin and cytokeratin‐18, indicating that they were of fibroblast origin. The population doubling time of skin fibroblasts from wild buffalo was significantly (p < 0.05) higher, and the cell proliferation rate was significantly (p < 0.05) lower compared with that of skin fibroblasts from domestic buffalo. Neither the cleavage (92.6 ± 2.0% vs 92.8 ± 2.0%) nor the blastocyst rate (42.4 ± 2.4% vs 38.7 ± 2.8%) was significantly different between the intraspecies cloned embryos produced using skin fibroblasts from domestic buffalo and interspecies cloned embryos produced using skin fibroblasts from wild buffalo. However, the total cell number (TCN) was significantly (p < 0.05) lower (192.0 ± 25.6 vs 345.7 ± 42.2), and the apoptotic index was significantly (p < 0.05) higher (15.1 ± 3.1 vs 8.0 ± 1.4) for interspecies than that for intraspecies cloned embryos. Following vitrification in open‐pulled straws (OPS) and warming, although the cryosurvival rate of both types of cloned embryos, as indicated by their re‐expansion rate, was not significantly different (34.8 ± 1.5% vs 47.8 ± 7.8), the apoptotic index was significantly (p < 0.05) higher for vitrified–warmed interspecies than that for corresponding intraspecies cloned embryos (48.9 ± 7.2 vs 23.9 ± 2.8). The global level of H3K18ac was significantly (p < 0.05) lower in interspecies cloned embryos than that in intraspecies cloned embryos. The expression level of HDAC1, DNMT3a and CASPASE3 was significantly (p < 0.05) higher, that of P53 was significantly (p < 0.05) lower in interspecies than in intraspecies embryos, whereas that of DNMT1 was similar between the two types of embryos. In conclusion, these results demonstrate that wild buffalo embryos can be produced by iSCNT.     

The fat that matters: Soil food web analysis using fatty acids and their carbon stable isotope signature

Chemical taxonomy based upon the composition of lipids is widely applied to investigate microbial communities and fatty acids have recently been employed to connect soil microbial and faunal food webs as well as to elucidate functional groups at higher trophic levels. The additional use of compound-specific isotopic analysis of ¹³C/¹²C ratios in fatty acids allows assessing specific trophic links and belowground carbon fluxes. In this review systematic patterns and processes underlying variations in the composition of fatty acids and their ¹³C/¹²C ratio are described. The emphasis is on biomarker fatty acids, their incorporation and modification, effects of pool size, and analytical methods. Further development of the application of fatty acid profiling to soil ecology should include both advances in experimental research and growth of theory. Accordingly, areas in which future experimentation can lead to progress in soil food web analysis are identified. Overall, combining fatty acid biomarker and their isotopic ratios will allow detailed insight into belowground trophic interactions.