| 1. |
- Elving, Josefine
(author)
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Pathogen inactivation and regrowth in organic waste during biological treatment
- 2009
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Licentiate thesis (other academic/artistic)abstract
- After proper sanitation treatment, organic wastes such as animal by-products, e.g.catering waste, slaughterhouse waste and manure can be used as fertilisers and soil conditioners and thereby contribute to a sustainable society. However, organic waste may contain pathogenic microorganisms and can thus present a health risk to both humans and animals if not properly treated. In the present thesis regrowth potential of Salmonella Typhimurium, Enterococcus spp. and coliforms in organic waste at psychrophilic and mesophilic temperatures and the time and temperature combinations required for pathogen inactivation during thermal treatments was investigated. This was done with the aim to contribute to hygienically safe recycling of organic waste. Pathogen growth was observed in active compost material as well as in fresh cattle manure. The growth potential decreased with increased maturity of the compost. In thermal treatment of fresh cattle manure, a treatment temperature of 52°C and a retention time of 17.2 h or a temperature of 55°C during 16.9 h were needed to achieve the reduction targets set by current EU regulation in terms of bacterial reduction. However, this time and temperature combination was not sufficient to achieve the reduction target of 3 log10 for parvovirus as a thermoresistant virus. The inactivation rate of Salmonella Senftenberg W775 and Enterococcus spp. were found to increase with increased moisture content whereas the opposite relationship between inactivation rate and moisture content was observed for viruses.
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| 2. |
- Emmoth, Eva
(author)
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Virus inactivation : evaluation of processes used in biowaste management
- 2010
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Licentiate thesis (other academic/artistic)abstract
- Animal by-products (ABP) Category 3 includes hatchery waste, and also slaughterhouse waste and manure, aimed for use in biogas production. In order to be used as fertilisers, they must be sanitised to reduce pathogenic microorganisms. The initial European regulations regarding processing standards for ABP intended for use in e.g. biogas plants (EC No. 1774/2002) stipulated thermal treatment at 70°C for 60 min. A subsequent amendment (EC No. 208/2006) stated that a validated treatment process may be used if it can show a reduction in thermo-resistant viruses of at least 3 log10, whenever deamed a risk. Thermal treatments of biogas substrate at 70°C and at 55°C, using porcine parvovirus and swine vesicular disease virus, were performed. As a chemical sanitisation process regarding hatchery waste, ammonia inactivation was tested using the highly pathogenic avian influenza virus H7N1 and the low pathogenic avian influenza virus H5N3. Models for other avian pathogenic ssRNA viruses were bovine parainfluenza virus 3, feline calicivirus and feline coronavirus. As possible indicators for monitoring virus inactivation, bacteriophages MS2, ΦX174, and 28b were evaluated. Thermal treatment at 70°C for 60 min inactivated porcine parvovirus by 2.6 log10, while phage 28b was unaffected. Swine vesicular disease virus was undetectable after 30 min. Using too thermostable viruses as models for sufficient virus reduction in thermal treatments regarding Category 3 ABP materials and manure intended for biogas or composting plants, according to EU regulations, would make demands on other time-temperature combinations very strict. All viruses tested were efficiently inactivated by ammonia treatment in hatchery waste, while phage ΦX174 proved too conservative to be used as indicator. Using phage MS2 as a stable indicator to monitor a 3 log10 reduction of ssRNA virus showed that addition of 0.5% w/w ammonia is required, followed by storage for at least 31 h at ≥14°C. In case of an outbreak of e.g. avian influenza, storage for two days at the same conditions was estimated.
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| 3. |
- Mahgiubi, Shaima A. M.
(author)
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Effects of octylphenol on sexual development and reproduction in zebrafish
- 2011
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Licentiate thesis (other academic/artistic)abstract
- Anthropogenic chemicals released into the aquatic environment can disrupt the normal function(s) of an organism's endocrine system and thereby adversely affect reproduction and development. This has led to the development of robust fish tests to detect and assess endocrine active chemicals. This thesis investigated developmental and reproductive effects of exposure to octylphenol (OP) in zebrafish. Zebrafish were exposed to OP in a Fish Sexual Development Test (FSDT) to investigate effects on sexual development. The main endpoints were vitellogenin induction and gonad development, including sex ratios. Zebrafish were also exposed to OP in a Fish Full Life Cycle test (FFLC) and a Fish Short Term Reproduction Assay (FSTRA) to investigate effects on different reproductive processes; i.e. gonad development, sexual phenotype and reproductive performance. Exposures to OP resulted in shifts in sex ratios, suppression in ovarian development, impairment in reproduction and reduction in growth, whereas no effects on VTG levels were observed. Conclusively, both the FSDT and FFLC test, but not the FSTRA, were sensitive tests for detection of endocrine-related effects of the weak estrogen OP. This thesis shows that OP, acting as a weak estrogen, has a negative impact on sexual development and maturation as well as reproduction in zebrafish.
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| 4. |
- Metreveli, Giorgi
(author)
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Swine influenza A virus subtype H1N2 in Sweden
- 2012
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Licentiate thesis (other academic/artistic)abstract
- The influenza A virus subtypes H1N1, H1N2 and H3N2 are prevalent in pig populations worldwide. All scientific data point towards swine as the key host species when new human influenza pandemics arise. All previous pandemics have been suggested to evolve in pigs from viral genes of avian, human and porcine origin. Therefore, it is of major importance to monitor the evolution of swine influenza viruses in pigs, and in particular monitor hallmarks of species adaptation to humans.The scope of this project was to increase the understanding of the genetics of swine influenza virus (SIV), with special emphasis on its zoonotic potential, and to investigate the importance of different viral gene markers for species specificity and adaptation. Since clinical manifestation of swine influenza is rare in Sweden, and SIV strains are of particular concern due to the novel human H1N1 epidemic, viruses were isolated in primary swine kidney or Madin Darby Canine Kidney (MDCK) cells, based on standard protocols and the isolates were subjected to full genome sequencing and comparative sequence analysis of the viral genomes. The results describe the analysis of the whole genome sequences from two swine influenza viruses isolated from Sweden in 2009 and 2010. Moreover, this study demonstrates, for the first time, natural reassortment in H1N2 viruses in the pig populations of Sweden. Biological characterization of the two viruses revealed a weaker growing potential, compared to the Swedish 2002 H1N1 isolate. Sequence comparison revealed significant differences between the two consecutive H1N2 isolates. The most remarkable of these was a truncated coding region for PB1-F2 in the earlier isolates and a full length coding region in the more recent isolates. In order to determine the effect of these viruses on the swine industry and on influenza ecology, further surveillance investigations and detailed analyses are needed.
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| 5. |
- Yagdiran, Yagmur
(author)
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Transport proteins in mammary epithelial cells : studies in murine (HC11) and bovine (BME-UV) cells - effects of prochloraz
- 2015
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Licentiate thesis (other academic/artistic)abstract
- Transporters localized in membranes of secreting mammary epithelial cells are involved in delivery of essential nutrients into milk. However, drugs and other xenobiotics may be substrates of these transporters and thus be actively secreted into milk, which may pose a health threat to breastfed infants and dairy consumers. Aims of the thesis were to determine expressions of drug transporters in mammary gland tissue and to assess mammary cell models for studies of these proteins. Gene expressions of members of the ABC (BCRP/ABCG2, MDR1/ABCB1, MRP1/ABCC1) and SLC (OATP1A2/SLCO1A2, OCTN1/SLC22A4, OCT1/SLC22A1) families were measured in murine and bovine mammary tissue and in murine (HC11) and bovine (BME-UV) mammary epithelial cell lines. BCRP function was assessed by transport experiments with mitoxantrone (MX) in HC11 cells. Effects of the imidazole fungicide prochloraz on transporter expression and function in HC11 and BME-UV cells were examined. Expressions of BCRP and OCT1 in murine mammary glands were increased during gestation and lactation, whereas MDR1, MRP1, OATP1A2 and OCTN1 were decreased, compared to expression in virgins. All transporters measured in mammary glands of mice were detected in bovine mammary tissue. All transporters investigated in vivo were also detected in HC11 cells, while only MDR1 and MRP1 were detected in BME-UV cells. Differentiation of HC11 cells resulted in increased BCRP protein expression, while MDR1 expression was reduced. The BCRP inhibitor elacridar reduced secretion and increased accumulation of MX in both undifferentiated and differentiated HC11 cells. An increased accumulation of MX was observed in BCRP gene silenced HC11 cells. Prochloraz treatment induced MDR1 gene expression and protein function in both differentiated HC11 and BME-UV cells, resulting in decreased accumulation of the MDR1 substrate digoxin. In conclusion, we demonstrated that the HC11 and BME-UV mammary cell models are valuable tools for identifying substrates, inhibitors and inducers of transport proteins expressed in the mammary epithelium during lactation. The models can be used both to examine if chemical compounds are actively transported into milk and if they disrupt the normal function of transporters which may result in a disturbed delivery of essential nutrients into milk.
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