| 1. |
- Axelsson Olsson, Diana, et al.
(författare)
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Amoebae and algae can prolong the survival of Campylobacter species in co-culture
- 2010
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Ingår i: Experimental parasitology. - : Elsevier BV. - 0014-4894 .- 1090-2449. ; 126:1, s. 59-64
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Tidskriftsartikel (refereegranskat)abstract
- Several species of free-living amoebae can cause disease in humans. However, in addition to the direct pathogenicity of e.g. Acanthamoebae and Naegleria species, they are recognized as environmental hosts, indirectly involved in the epidemiology of many pathogenic bacteria. Although several studies have demonstrated intracellular survival of many different bacteria in these species, the extent of such interactions as well as the implications for the epidemiology of the bacterial species involved, are largely unknown and probably underestimated. In this study, we evaluated eight different unicellular eukaryotic organisms, for their potential to serve as environmental hosts for Campylobacter species. These organisms include four amoebozoas (Acanthamoeba polyphaga, Acanthamoeba castellanii, Acanthamoeba rhysodes and Hartmanella vermiformis), one alveolate (Tetrahymena pyriformis), one stramenopile (Dinobryon sertularia), one eugoenozoa (Euglena gracilis) and one heterolobosea (Naegleria americana). Campylobacter spp. including Campylobacter jejuni, Campylobacter coli and Campylobacter lari are the most common cause of gastroenteritis in the western world. Survival and replication of these three species as well as Campylobacter hyointestinalis were assessed in co-cultures with the eukaryotic organisms. Campylobacter spp. generally survived longer in co-cultures, compared to when incubated in the corresponding growth media. The eukaryotic species that best promoted bacterial survival was the golden algae D. sertularia. Three species of amoebozoas, of the genus Acanthamoeba promoted both prolonged survival and replication of Campylobacter spp. The high abundance in lakes, ponds and water distribution networks of these organisms indicate that they might have a role in the epidemiology of campylobacteriosis, possibly contributing to survival and dissemination of these intestinal pathogens to humans and other animals. The results suggest that not only C. jejuni, but a variety of Campylobacter spp. can interact with different eukaryotic unicellular organisms.
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| 2. |
- Axelsson Olsson, Diana, et al.
(författare)
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Increase in Acid Tolerance of Campylobacter jejuni through Coincubation with Amoebae
- 2010
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 76:13, s. 4194-4200
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacter jejuni is a recognized and common gastrointestinal pathogen in most parts of the world. Human infections are often food borne, and the bacterium is frequent among poultry and other food animals. However, much less is known about the epidemiology of C. jejuni in the environment and what mechanisms the bacterium depends on to tolerate low pH. The sensitive nature of C. jejuni stands in contrast to the fact that it is difficult to eradicate from poultry production, and even more contradictory is the fact that the bacterium is able to survive the acidic passage through the human stomach. Here we expand the knowledge on C. jejuni acid tolerance by looking at protozoa as a potential epidemiological pathway of infection. Our results showed that when C. jejuni cells were coincubated with Acanthamoeba polyphaga in acidified phosphate-buffered saline (PBS) or tap water, the bacteria could tolerate pHs far below those in their normal range, even surviving at pH 4 for 20 h and at pH 2 for 5 h. Interestingly, moderately acidic conditions (pH 4 and 5) were shown to trigger C. jejuni motility as well as to increase adhesion/internalization of bacteria into A. polyphaga. Taken together, the results suggest that protozoa may act as protective hosts against harsh conditions and might be a potential risk factor for C. jejuni infections. These findings may be important for our understanding of C. jejuni passage through the gastrointestinal tract and for hygiene practices used in poultry settings.
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| 3. |
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| 4. |
- Björnsson, Lovisa, et al.
(författare)
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Förbehandling av lignocellulosarika råvaror vid biogasproduktion - Nyckelaspekter vid jämförande utvärdering
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I biogassektorn finns ett ökande behov av och en ökande konkurrens om råvaror, och intresset för användning av odlingsrester, vall, mellangrödor mm som biogasråvara ökar. Gemensamt för dessa råvaror är att de är fiberrika, dvs. har ett högt innehåll av lignocellulosa, vilket gör att det är osannolikt att de skulle användas för biogasproduktion utan förbehandling. Ett antal förbehandlingstekniker har introducerats på marknaden under senare år, och både företagsdrivna projekt och forskningsprojekt kring utvärdering av en eller flera förbehandlingstekniker pågår. Utvärderingarna läggs dock upp med olika utgångspunkter och metoder så att utkomster från olika projekt blir omöjliga att jämföra. Att utreda frågan om hur man utvärderar och jämför olika förbehandlingsmetoder ur teknik-, ekonomi-, energi- och miljöperspektiv är därför angeläget. Syftet med denna förstudie är att peka ut nyckelaspekter som är viktiga för att möjliggöra jämförande utvärdering av olika förbehandlingsmetoder samt att inspirera aktörer till att vilja medverka till att ta ett samlat grepp i frågan. Ett förslag till upplägg för vidare forskning, utveckling och demonstration presenteras. Arbetet med förstudien har finansierats genom Energimyndigheten.
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| 5. |
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| 6. |
- Björnsson, Lovisa
(creator_code:cre_t)
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Pretreating non-wood lignocellulosic material (e.g. bagasse) to produce ethanol, comprises adding organic acid or organic acid-producing bacteria to lignocellulosic material, and storing and heating the organic acid-impregnated material
- 2012
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- NOVELTY - Pretreating non-wood lignocellulosic material containing less than 5 wt.% starch or sugar for producing ethanol from lignocellulose, comprises: (a) adding organic acid or organic acid-producing bacteria to the lignocellulosic material; (b) storing the lignocellulosic material in presence of organic acid for at least 2 weeks in an atmosphere of less than 5% oxygen to obtain organic acid-impregnated material; and (c) heating the organic acid-impregnated material at a temperature of at least 190 degrees C for at least 5 minutes to obtain pretreated lignocellulosic material. USE - The method is useful for pretreating non-wood lignocellulosic material to produce ethanol, where the non-wood lignocellulosic material is bagasse (preferably sugar cane bagasse or sweet Sorghum bagasse), sugar cane trash, wheat straw, rice straw, Sorghum species, Arundo, Miscanthus or agricultural residues (all claimed). ADVANTAGE - The method: avoids the need of inorganic acid or base (sulfur dioxide), and utilizes containers which are less corrosion resistant, hence economical; has higher net energy gain; utilizes organic acid which is biodegradable, and produces degradation products (e.g. 5-hydroxymethylfurfural and furfural which acts as inhibitory substances in the subsequent fermentation process), thus environmentally friendly. DETAILED DESCRIPTION - Pretreating non-wood lignocellulosic material containing less than 5 wt.% starch or sugar for producing ethanol from lignocellulose, comprises: (a) adding organic acid or organic acid-producing bacteria to the lignocellulosic material; (b) storing the lignocellulosic material in the presence of organic acid for at least 2 weeks in an atmosphere of less than 5% oxygen to obtain organic acid-impregnated material; and (c) heating the organic acid-impregnated material at a temperature of at least 190 degrees C for a period of at least 5 minutes to obtain pretreated lignocellulosic material, where no inorganic acid or base including sulfur dioxide is added in the method.
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| 7. |
- Demirel, Isak, 1987-, et al.
(författare)
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Nitric oxide activates IL-6 production and expression in human renal epithelial cells
- 2012
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Ingår i: American Journal of Nephrology. - Basel, Switzerland : S. Karger. - 0250-8095 .- 1421-9670. ; 36:6, s. 524-530
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Increased nitric oxide (NO) production or inducible form of NO synthase activity have been documented in patients suffering from urinary tract infection (UTI), but the role of NO in this infection is unclear. We investigated whether NO can affect the host response in human renal epithelial cells by modulating IL-6 production and mRNA expression. Methods: The human renal epithelial cell line A498 was infected with a uropathogenic Escherichia coli (UPEC) strain and/or the NO donor DETA/NO. The IL-6 production and mRNA expression were evaluated by ELISA and real-time RT-PCR. IL-6 mRNA stability was evaluated by analyzing mRNA degradation by real-time RT-PCR.Results: DETA/NO caused a significant (p < 0.05) increase in IL-6 production. Inhibitors of p38 MAPK and ERK1/2 signaling, but not JNK, were shown to significantly suppress DETA/NO-induced IL-6 production. UPEC-induced IL-6 production was further increased (by 73 ± 23%, p < 0.05) in the presence of DETA/NO. The IL-6 mRNA expression increased 2.1 ± 0.17-fold in response to DETA/NO, while the UPEC-evoked increase was pronounced (20 ± 4.5-fold). A synergistic effect of DETA/NO on UPEC-induced IL-6 expression was found (33 ± 7.2-fold increase). The IL-6 mRNA stability studies showed that DETA/NO partially attenuated UPEC-induced degradation of IL-6 mRNA.Conclusions: NO was found to stimulate IL-6 in renal epithelial cells through p38 MAPK and ERK1/2 signaling pathways and also to increase IL-6 mRNA stability in UPEC-infected cells. This study proposes a new role for NO in the host response during UTI by modulating the transcription and production of the cytokine IL-6.
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| 8. |
- Gissén, Charlott, et al.
(författare)
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Comparing energy crops for biogas production Yields, energy input and costs in cultivation using digestate and mineral fertilisation
- 2014
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Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 64, s. 199-210
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of six crops grown in southern Sweden for biogas production (hemp, sugar beet, maize, triticale, grass/clover ley, winter wheat) showed varying performance regarding methane yield per hectare and energy input and costs in the production and supply of crops as biogas feedstock. The highest biomass and biogas yield was observed for sugar beet. Crops with lower risk of negative environmental impact in cultivation, such as ley and hemp, produced less than half the methane energy yield per hectare. Triticale, also having less risk of negative environmental impact, gave an energy yield similar to that of winter wheat grain and maize. Replacing most of the mineral fertiliser with biogas digestate did not, with the exception for hemp, influence crop yields per hectare, but energy input in cultivation decreased by on average 34% for the six crops tested. For hemp and sugar beet the biogas feedstock costs for the freshly harvested crop per GJ methane were close to that of the economic reference crop, winter wheat grain. For maize, beet tops and first and second year ley, the feedstock costs were lower, and for triticale much lower. When ensiled crops were used for biogas the feedstock costs increased and only those of triticale silage remained slightly lower than the cost of dried wheat grain. However, all feedstock costs were so high that profitable biogas production based solely on ensiled crops would be difficult to achieve at present Swedish biogas sales prices. (c) 2014 Elsevier Ltd. All rights reserved.
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| 9. |
- Jourdain, Elsa, et al.
(författare)
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Influenza Virus in a Natural Host, the Mallard : Experimental Infection Data
- 2010
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- Wild waterfowl, particularly dabbling ducks such as mallards (Anas platyrhynchos), are considered the main reservoir of low-pathogenic avian influenza viruses (LPAIVs). They carry viruses that may evolve and become highly pathogenic for poultry or zoonotic. Understanding the ecology of LPAIVs in these natural hosts is therefore essential. We assessed the clinical response, viral shedding and antibody production of juvenile mallards after intra-esophageal inoculation of two LPAIV subtypes previously isolated from wild congeners. Six ducks, equipped with data loggers that continually monitored body temperature, heart rate and activity, were successively inoculated with an H7N7 LPAI isolate (day 0), the same H7N7 isolate again (day 21) and an H5N2 LPAI isolate (day 35). After the first H7N7 inoculation, the ducks remained alert with no modification of heart rate or activity. However, body temperature transiently increased in four individuals, suggesting that LPAIV strains may have minor clinical effects on their natural hosts. The excretion patterns observed after both reinoculations differed strongly from those observed after the primary H7N7 inoculation, suggesting that not only homosubtypic but also heterosubtypic immunity exist. Our study suggests that LPAI infection has minor clinically measurable effects on mallards and that mallard ducks are able to mount immunological responses protective against heterologous infections. Because the transmission dynamics of LPAIVs in wild populations is greatly influenced by individual susceptibility and herd immunity, these findings are of high importance. Our study also shows the relevance of using telemetry to monitor disease in animals.
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| 10. |
- Kreuger, Emma, et al.
(författare)
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Anaerobic digestion of industrial hemp-Effect of harvest time on methane energy yield per hectare
- 2011
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Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 35:2, s. 893-900
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Tidskriftsartikel (refereegranskat)abstract
- There is a worldwide emphasis to increase the share of renewable transportation fuels. When using agricultural land for production of renewable transportation fuels, the energy output per hectare for different crops and transportation fuels is a crucial factor. In this study, the gross methane energy yield per hectare from anaerobic digestion of industrial hemp (Cannabis sativa L.), was determined at four different harvest times between July and October in Southern Sweden, a cold climate region. The biomass yield was determined for three years and the methane yield was determined for two years through the biochemical methane potential test. The highest biomass yield, 16 tonnes dry matter per hectare on an average, and the highest methane energy yield per hectare was achieved when the hemp was harvested in September or October, with an average gross methane energy yield of 136 +/- 24 GJ per hectare. There was no significant difference in the specific methane yield between the harvest times; the average being 234 +/- 35 m(3) per tonne volatile solids. Biogas from hemp turned out to be a high yielding alternative to the currently dominating renewable transportation fuels produced from crops grown in Sweden: ethanol from wheat and biodiesel from rapeseed. (C) 2010 Elsevier Ltd. All rights reserved.
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