| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Forslund, Ola, et al.
(författare)
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The nasal mucosa contains a large diversity of human papillomavirus from the Beta- and Gammapapillomavirus genera.
- 2013
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 208:8, s. 1335-1341
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Tidskriftsartikel (refereegranskat)abstract
- Background. Human papillomavirus (HPV) types from the Beta- and Gammapapillomavirus genera are common at cutaneous sites. The aim of this study was to analyze the prevalence of these HPV types in oral and nasal samples.Methods. Nasal and oral samples were taken from 312 volunteers of Danish health-care staff (240 women and 72 males, with mean age of 42 years). Of these 311 oral and 304 nasal samples were eligible for HPV DNA analysis.HPV types were detected by the use of PCR with MGP- and FAP-primers and identified by Luminex (MGP), and direct sequencing or cloning prior to sequencing (FAP).Results. HPV DNA was detected in 6% of the oral samples and 50% of the nasal samples. A large diversity of 75 HPV types/putative HPV types was identified. HPV types within genus Alpha-, Beta- and Gammapapillomaviruses were detected in 3%, 31%, and 23% of the nasal samples, respectively. A putative subtype of HPV76, originally isolated from a feline oral SCC, was detected in seven nasal samples.Conclusion. A large spectrum of HPV types from Beta- and Gammapapillomavirus have tropism for the nasal mucosa. The implication of the relatively high prevalence of these viruses in the nasal mucosa is unknown.
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| 3. |
- Kofoed, Kristian, et al.
(författare)
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Low Prevalence of Oral and Nasal Human Papillomavirus in Employees Performing CO2-laser Evaporation of Genital Warts or Loop Electrode Excision Procedure of Cervical Dysplasia
- 2015
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 1651-2057 .- 0001-5555. ; 95:2, s. 173-176
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Tidskriftsartikel (refereegranskat)abstract
- Risk of human papillomavirus (HPV) transmission during laser vaporisation of genital warts or loop electrode excision procedure is controversial. An oral rinse, a nasal swabs, history of HPV-related diseases and data on HPV exposure were collected from 287 employees at departments of dermato-venerology and gynaecology in Denmark. A mucosal HPV type was found among 5.8% of employees with experience of laser treatment of genital warts as compared to 1.7% of those with no experience (p=0.12). HPV prevalence was not higher in employees participating in electrosurgical treatment or cryotherapy of genital warts, or loop electrode excision procedure compared with those who did not. HPV 6 or 11 were not detected in any samples. Hand warts after the age of 24 years was more common among dermatology than among non-dermatology personnel (18% vs. 8.0% P=0.03). Mucosal HPV types are infrequent in the oral and nasal cavity of health care personnel, however, employees at departments of dermato-venereology are at risk of acquiring hand warts.
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| 4. |
- Kofoed, Kristian, et al.
(författare)
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Prevalence of Human Papillomavirus in Anal and Oral Sites Among Patients with Genital Warts
- 2014
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 1651-2057 .- 0001-5555. ; 94:2, s. 207-211
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Tidskriftsartikel (refereegranskat)abstract
- Genital warts are caused by human papillomavirus (HPV). HPV is a leading cause of anogenital malignancies and a role of HPV in the aetiology of oro-pharyngeal cancers has been demonstrated. The frequency of oral HPV infection in patients with genital warts and the association between concomitant genital, anal and oral infection is unclear. A total of 201 men and women with genital wart-like lesions were recruited. Swab samples were obtained from the genital warts and the anal canal and an oral rinse was collected. Anal HPV was found in 46.2% and oral HPV in 10.4% of the participants. Concordance between anal and genital wart HPV types was 78.1%, while concordance between oral and genital wart types was 60.9%. A lower concordance of 21.7% was observed between anal and oral HPV types. Significantly more women than men had multiple HPV types and anal HPV. In conclusion, extra genital HPV is common in patients with genital warts. A gender inequality seems to exist.
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| 5. |
- Zettergren, Henning, et al.
(författare)
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Electron-Capture-Induced Dissociation of Microsolvated Di- and > Tripeptide Monocations : Elucidation of Fragmentation Channels from > Measurements of Negative Ions
- 2009
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Ingår i: ChemPhysChem. - : Wiley. - 1439-4235 .- 1439-7641. ; 10:9-10, s. 1619-1623
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Tidskriftsartikel (refereegranskat)abstract
- The branching ratio between ammonia loss and NCα bond cleavage of singly charged microsolvated peptides after electron capture from cesium depends on the solvent molecule attached. Density functional calculations reveal that for [GA+H]+(CE) (G=glycine, A=alanine, CE=crown ether), the singly occupied molecular orbital of the neutral radical is located mainly on the amide group (see picture). The results from an experimental study of bare and microsolvated peptide monocations in high-energy collisions with cesium vapor are reported. Neutral radicals form after electron capture from cesium, which decay by H loss, NH3 loss, or NCα bond cleavage into characteristic z. and c fragments. The neutral fragments are converted into negatively charged species in a second collision with cesium and are identified by means of mass spectrometry. For protonated GA (G=glycine, A=alanine), the branching ratio between NH3 loss and NCα bond cleavage is found to strongly depend on the molecule attached (H2O, CH3CN, CH3OH, and 18-crown-6 ether (CE)). Addition of H2O and CH3OH increases this ratio whereas CH3CN and CE decrease it. For protonated AAA ([AAA+H]+), a similar effect is observed with methanol, while the ratio between the z1 and z2 fragment peaks remains unchanged for the bare and microsolvated species. Density functional theory calculations reveal that in the case of [GA+H]+(CE), the singly occupied molecular orbital is located mainly on the amide group in accordance with the experimental results.
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