| 1. |
- Fervier, Veronica, et al.
(författare)
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Evaluating Nutrient Reduction, Grazing and Barley Straw as Measures Against Algal Growth
- 2020
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Ingår i: Wetlands (Wilmington, N.C.). - : SPRINGER. - 0277-5212 .- 1943-6246. ; 40:1, s. 193-202
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Tidskriftsartikel (refereegranskat)abstract
- The aim of our study was to experimentally investigate whether it is possible to reduce nuisance growth of filamentous algae in freshwater ecosystems. We used an experimental set-up mimicking a shallow pond system and performed a field investigation in the eutrophic moat of Krapperup castle (Southern Sweden), which exemplifies an extremely impaired ecosystem with ample growth of filamentous green algae. The indoor experiment tested three treatments: I) reduced nutrient concentrations, II) invertebrate grazers and III) addition of barley straw, which may constitute measures against filamentous algal growth and thereby improve the quality of the ecosystem services provided by water bodies. Our results show a decrease in cyanobacteria and diatom abundances in all mesocosms as filamentous algae biomass increased, suggesting that the microalgae suffered from nutrient and light competition with filamentous algae. A tendency for lower filamentous algae final biomass, as well as coverage, was observed in the treatment where the concentration of nutrients was reduced. Grazers treatment showed a tendency to inhibit filamentous algae growth on artificial macrophytes towards the end of the experiment, suggesting that snails initially fed on their preferred food source (diatoms), until it was almost depleted and then started to feed on filamentous algae. Interestingly, the barley straw treatment was the only treatment promoting macrophytes growth and enhancing diatom biomass, but this did not affect filamentous algae biomass. However, the ratio between filamentous algae and macrophyte final biomasses was significantly lower in the straw treatment. In a broader context, it is likely that in a long-term perspective the positive effect of barley straw on macrophyte growth will promote a shift from dominance by filamentous algae to macrophytes as main primary producer. Moreover, our experiment shows that barley straw may be effective in reducing cyanobacterial growth, which may lead to improved water quality and thereby ecosystem services, such as supporting and cultural ecosystem services, since cyanobacteria may produce potent toxins and pose a serious risk to human and animal health. Altogether, our experimental results have important implications for the challenge of reversing nuisance filamentous algal blooms in highly eutrophic systems.
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| 2. |
- Jurstrand, Margaretha, et al.
(författare)
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Characterization of Chlamydia trachomatis omp1 genotypes among sexually transmitted disease patients in Sweden
- 2001
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 39:11, s. 3915-3919
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Tidskriftsartikel (refereegranskat)abstract
- A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed. DNA was extracted from urogenital or urine samples using a Chelex-based method, and an approximately 1,100-bp-long fragment from the omp1 gene was directly amplified and sequenced. Genotyping was performed by BLAST similarity search, and phylogenetic tree analysis was used to illustrate the evolutionary relationships between clinical isolates and reference strains. The method was used to determine the genotypes of C. trachomatis in 237 positive urogenital and/or urine specimens collected at a Swedish sexually transmitted disease clinic during 1 year. The most common genotypes corresponded to serotypes E (47%) and F (17%). The omp1 gene was highly conserved for genotype E (106 of 112 samples without any mutation) and F (41 of 42 samples without any mutation) strains but appear slightly less conserved for genotypes G (n = 6) and H (n = 6), where the sequences displayed one to four nucleotide substitutions relative to the reference sequence. Genotyping of samples collected at the follow-up visit indicated that two patients had become reinfected, while three other patients suffered treatment failure or reinfection. One woman appeared to have a mixed infection with two different C. trachomatis strains. This omp1 genotyping method had a high reproducibility and could be used for epidemiological characterization of sexually transmitted Chlamydia infections.
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| 3. |
- Li, Jing, et al.
(författare)
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Nutrient control to prevent the occurrence of cyanobacterial blooms in a eutrophic lake in Southern Sweden, used for drinking water supply
- 2018
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Control of nutrients, mainly nitrogen (N) and phosphorus (P), plays a significant role in preventing cyanobacterial blooms (harmful algal blooms (HABs)). This study aims at evaluating changes in the risk of the occurrence of cyanobacterial blooms and advancing the understanding of how nitrogen and phosphorus affect the growth of cyanobacteria in a eutrophic lake, Lake Vombsjön, in southern Sweden. Our results show that TP (total phosphorus) has stronger positive correlation with cyanobacteria biomass than DIP (dissolved inorganic phosphorus); DIN (dissolved inorganic nitrogen) has a stronger negative correlation with cyanobacteria biomass than TN (total nitrogen); and DIN:TP has a stronger negative correlation with cyanobacteria biomass than TN:TP. The highest amount of cyanobacteria biomass, aboveWHO(World Health Organization) Alert Level 2 (10mm3/L) for drinking water correspond to the DIP/TP ratio below 10. To diminish the growth of cyanobacteria in Lake Vombsjön, TP and DIN control should be in focus, preferably a TP below 20 μg/L, and the DIN:TP ratio should be maintained at a level of at least above 10, but preferably above 50, thereby reducing the likelihood for a nitrogen limiting situation which may favor cyanobacteria dominating blooms.
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| 4. |
- Liuba, Petru, et al.
(författare)
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Acute Chlamydia pneumoniae infection causes coronary endothelial dysfunction in pigs.
- 2003
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Ingår i: Atherosclerosis. - 1879-1484. ; 167:2, s. 215-222
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Tidskriftsartikel (refereegranskat)abstract
- Background: Coronary endothelial dysfunction contributes to the pathogenesis of acute coronary syndromes (ACSs). Acute Chlamydia pneumoniae infection has been epidemiologically associated with ACS. In this study, we investigated whether acute C. pneumoniae infection could alter the endothelial vasomotor function of porcine coronary vessels. Methods and results: Twenty pigs, 7–9 kg in weight, were inoculated intratracheally with C. pneumoniae (n=12) or saline (n=8), and investigated at 3 days (five infected/four non-infected) and 2 weeks (5+2 infected/four non-infected) after inoculation. The endothelium-dependent reactivity of coronary microcirculation was assessed at both time points by measuring peak coronary flow velocity (CFV) in response to bradykinin, before and after infusions with glutathione, an antioxidant, and Image-arginine, a substrate for nitric oxide synthase (NOS). CFV after bradykinin was significantly decreased in infected animals at both time points. At 2 weeks, both glutathione and Image-arginine significantly improved CFV after bradykinin. CFV after sodium nitroprusside (SNP) was similar in both groups. At 3 days, the relaxation responses of bradykinin-induced pre-contracted left anterior descending (LAD) coronary rings to bradykinin were significantly less in infected animals. NG-nitro-Image-arginine-methyl-ester, an NOS inhibitor, had significantly greater inhibitory effect on bradykinin-induced relaxation in infected animals. Plasma nitrate–nitrite and fibrinogen, and NOS activity from LAD coronary samples were significantly increased in infected animals. Conclusion: Acute C. pneumoniae infection causes endothelial dysfunction of both resistance and epicardial coronary vessels, and favours a pro-coagulant status. These effects could in part account for the epidemiologically suggested association between acute infection and ACS.
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| 5. |
- Liuba, Petru, et al.
(författare)
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Co-Infection with CHLAMYDIA PNEUMONIAE and HELICOBACTER PYLORI Results in Vascular Endothelial Dysfunction and Enhanced VCAM-1 Expression in ApoE-Knockout Mice.
- 2003
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 40:2, s. 115-122
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Tidskriftsartikel (refereegranskat)abstract
- <i>Background:</i> Upregulation of proinflammatory endothelial cell adhesion molecules and decreased bioactivity of endothelial nitric oxide (NO) are important in the pathogenesis of atherosclerosis. We investigated the effects of co-infection with <i>Chlamydia pneumoniae</i> and <i>Helicobacter pylori </i>on these two events in apoE-KO mice. <i>Methods:</i> Thirty-two apoE-KO mice, 8 weeks old, were equally divided into 4 groups. The first 2 groups were infected with either <i>C. pneumoniae</i> or <i>H. pylori,</i> while the 3rd group was infected with both <i>C. pneumoniae</i> and <i>H. pylori</i>. Mice from the 4th group and 4 wild-type mice served as controls. Thoracic and abdominal aortas were harvested after 10 weeks, and staining for vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 was analyzed by immunocytochemistry. The endothelial vasomotor responses of thoracic aortas to methacholine were studied in organ chambers in the absence and presence of <i>L</i>-NAME. The plasma levels of nitrate/nitrite were measured. <i>Results:</i> Staining for VCAM-1 was more intense at the branching sites of aortas from mice with co-infection than in mono-infected or noninfected apoE-KO mice. The relaxation responses to methacholine and the plasma levels of nitrate/nitrite were significantly less in the co-infected group than in the other groups (p < 0.05). <i>Conclusion:</i> Co-infection of apoE-KO mice with <i>C. pneumoniae</i> and <i>H. pylori</i> seems to be associated with impaired bioactivity of endothelial NO and increased expression of VCAM-1 at branching sites. The findings may suggest an additive interaction of these pathogens in atherogenesis.
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| 6. |
- Liuba, Petru, et al.
(författare)
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Effects of Bradykinin on Aortic Endothelial Function in ApoE-Knockout Mice With Chronic Chlamydia Pneumoniae Infection.
- 2007
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Ingår i: Circulation Journal. - : Japanese Circulation Society. - 1346-9843 .- 1347-4820. ; 71:9, s. 1480-1484
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Tidskriftsartikel (refereegranskat)abstract
- Background Impaired muscarinic receptor-mediated vasodilation is an important feature of early atherosclerosis. Earlier studies on apolipoprotein E-knockout mice (apoE-KO) mice suggested adverse effects of Chlamydia pneumoniae infection on the endothelial vasomotor responses of aortas to the muscarinic agonist methacholine. Using additional aorta samples the present study investigated the responses to bradykinin. Methods and Results ApoE-KO mice were repeatedly inoculated with either Chlamydia pneumoniae (C. pneumoniae) or saline. At 2, 6, and 10 weeks after the first inoculation, precontracted aorta rings from both groups were exposed to bradykinin in the absence and presence of L-NAME and diclofenac. In noninfected animals, the vasomotor responses to bradykinin were similar at all timepoints (p > 0.5). Compared with noninfected animals, the responses in infected animals tended to increase through the study period (p < 0.05 at 10 weeks). Although diclofenac and L-NAME had no effect in noninfected mice, they inhibited the responses to bradykinin in infected mice at 6 and, more markedly, 10 weeks (p < 0.05 for both). Conclusion Bradykinin stimulation of aorta endothelium from C. pneumoniae-infected apoE-KO animals appears to activate compensatory kinin receptor-related mechanisms that could involve nitric oxide and vasorelaxing prostanoids. Although the precise molecular mechanisms require further investigation, one could speculate that strategies increasing bradykinin availability might reverse the arterial dysfunction during chronic infectious disease.
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| 7. |
- Liuba, Petru, et al.
(författare)
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Endothelial dysfunction after repeated Chlamydia pneumoniae infection in apolipoprotein E-knockout mice
- 2000
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Ingår i: Circulation. - 1524-4539. ; 102:9, s. 1039-1044
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Arterial relaxation is largely regulated by endothelial nitric oxide (NO). Its diminished activity has been associated with incipient atherosclerosis. We investigated the endothelium-dependent relaxation of aorta in apolipoprotein E-knockout (apoE-KO) mice exposed to single or repeated Chlamydia pneumoniae inoculation. METHODS AND RESULTS: Forty-eight apoE-KO mice, 8 weeks old, were inoculated intranasally with C pneumoniae (n=24) or saline (n=24) every 2 weeks over a 6-week period. Twenty mice (10 infected and 10 controls) were killed at 2 weeks and 6 weeks, respectively, after the first inoculation. The smooth muscle tone of aortic rings was measured in vitro at both time points. The norepinephrine-precontracted thoracic aortic rings were successively exposed to methacholine in the absence and presence of N:(G)-nitro-L-arginine methyl ester (L-NAME) and diclofenac. The methacholine-induced relaxation was attenuated in the infected mice at 6 weeks in both the absence and presence of L-NAME (P:<0.05 and P:<0.01, respectively). When administered together with L-NAME, diclofenac enhanced the relaxation of the L-NAME-pretreated aortas in infected mice at 2 weeks (P:<0.05) but not in noninfected mice. The relaxation response from infected mice tended to differ in the same manner at 6 weeks (P:<0.1). No intimal thickening was detected at either time point. CONCLUSIONS: C pneumoniae impairs arterial endothelial function, and the NO pathway is principally involved. Cyclooxygenase-dependent vasoconstricting products may also account for the infection-induced impaired relaxation. These findings further support the role of C pneumoniae infection in atherosclerosis development.
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| 8. |
- Liuba, Petru, et al.
(författare)
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Protective effects of simvastatin on coronary artery function in swine with acute infection.
- 2006
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Ingår i: Atherosclerosis. - : Elsevier BV. - 1879-1484 .- 0021-9150. ; 186:2, s. 331-336
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Tidskriftsartikel (refereegranskat)abstract
- Background: The risk for coronary events may rise during acute infection. Perturbation in coronary endothelial function emerges as one important link. We investigated whether simvastatin could protect the coronary arterial function from the adverse effects of acute infection in swine. Methods: Coronary endothelium-dependent and -independent vasomotor responses were assessed by Doppler velocimetry in 12 Chlamydia pneunioniae-infected and 6 sham-infected swine 2 weeks after intratracheal inoculation. Half of animals from the infection group were pretreated with simvastatin (80 mg daily), while the remaining animals received placebo. The treatment was started 2 weeks prior to inoculation and Continued until the end of the Study. ANOVA was used for statistical calculations. Data are mean +/- S.D. Results: All animals inoculated with C. pneumoniae developed IgM antibodies against this organism. As compared to noninfected animals, peak-to-baseline coronary flow velocity (CFV) ratio after bradykinin was significantly decreased in infected animals regardless of statin treatment (1,p=0.01). Intracoronary 10(-6) M acetylcholine caused slight dilatory responses in both noninfected and infected-treated animals (CFV ratio: 1.6 +/- 0.2and 1.4 +/- 0.2, respectively: p > 0.1),while a velocity drop (CFV ratio: 0.7 +/- 0.1; p < 0.01 versus noninfected-infected and treated). indicating constriction, was observed in in fected-non treated animals; 10(-5) M acetylcholine caused vasoconstriction in all animals, with a significantly more prolonged response in the infected-non treated group (p < 0.01). Intracoronary adenosine and SNP induced similar dilatory responses in all groups (p > 0.5). There were no differences in markers of systemic inflammation (fibrinogen, amyloid, and CRP) and lipid profile (HDL, LDL and total cholesterol) between the groups (p > 0.2). Conclusion: Acute infection is associated with impairment of the muscarinic and kinin-related reactivity of coronary circulation. These functional abnormalities are in part prevented by simvastatin through mechanisms unrelated to lipid lowering. (c) 2005 Elsevier Ireland Ltd. All rights reserved.
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| 9. |
- Mårdh, Per-Anders, et al.
(författare)
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Is there a need for rescreening of patients treated for genital chlamydial infections?
- 2002
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Ingår i: International Journal of STD and AIDS. - : SAGE Publications. - 0956-4624 .- 1758-1052. ; 13:6, s. 363-367
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The present communication reviews reasons to perform rescreening of chlamydia-infected persons. It brings up difficulties to differentiate between relapse and reinfection. Studies on follow-up of chlamydia-positive cases after therapy are reviewed. It also highlights reasons for therapeutic failure, like compliance, pharmacological factors, including poor bioavailability, wrong dose regimens, lack of adherence to drug intake, neglect of partner notification and concomitant therapy in consorts, possible development of resistance to drugs generally prescribed, false negative or false positive diagnostic tests and reinfection from extra-genital not 'cured' sites. The review points to the need to establish programmes for routine rescreening of chlamydia-infected persons.
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| 10. |
- Nilsson, Anna C, et al.
(författare)
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Longitudinal clearance of seasonal influenza A viral RNA measured by real-time polymerase chain reaction in patients identified at a hospital emergency department.
- 2010
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 42, s. 679-686
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Tidskriftsartikel (refereegranskat)abstract
- Abstract To study influenza virus shedding during acute infection, viral load was longitudinally measured by quantitative PCR in nasal flocked swabs from patients with seasonal H3N2 influenza at a Swedish emergency department, including both hospitalized patients and outpatients. Influenza A was detected in 65/184 patients. Sampling was repeated every 3-4 days in 45 patients, with the aim of continuing sampling until day 12 after disease onset. Home visits were offered. Antibodies were measured on paired sera in 95/184 patients. Fifty percent of the patients remained polymerase chain reaction (PCR)-positive 8 days after disease onset in a Kaplan-Meier survival curve. The longest observed duration of viral shedding was 12 days. The average viral load was initially low, peaked on days 2-3 of disease and then declined. Viral decline results remained similar when all 15 (25%) oseltamivir-treated patients were excluded. Significant antibody titre changes were seen in all the 35 PCR verified cases with available paired sera and in 8 of the 58 patients with negative PCR tests on acute phase nasal samples. In conclusion, quantitative PCR testing indicated the presence of influenza virus for up to 12 days, which could have implications for disease transmission and infection control.
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