Interactions between different phytoplankton taxa and heterotrophic bacterial communities within aquatic environments can differentially support growth of various heterotrophic bacterial species. In this study, phytoplankton diversity was studied using traditional microscopic techniques and the bacterial communities associated with phytoplankton bloom were studied using High Throughput Sequencing (HTS) analysis of 16S rRNA gene amplicons from the V1-V3 and V3-V4 hypervariable regions. Samples were collected from Lake Akersvannet, a eutrophic lake in South Norway, during the growth season from June to August 2013. Microscopic examination revealed that the phytoplankton community was mostly represented by Cyanobacteria and the dinoflagellate Ceratium hirundinella. The HTS results revealed that Proteobacteria (Alpha, Beta, and Gamma), Bacteriodetes, Cyanobacteria, Actinobacteria and Verrucomicrobia dominated the bacterial community, with varying relative abundances throughout the sampling season. Species level identification of Cyanobacteria showed a mixed population of Aphanizomenon flos-aquae, Microcystis aeruginosa and Woronichinia naegeliana. A significant proportion of the microbial community was composed of unclassified taxa which might represent locally adapted freshwater bacterial groups. Comparison of cyanobacterial species composition from HTS and microscopy revealed quantitative discrepancies, indicating a need for cross validation of results. To our knowledge, this is the first study that uses HTS methods for studying the bacterial community associated with phytoplankton blooms in a Norwegian lake. The study demonstrates the value of considering results from multiple methods when studying bacterial communities.

We report the results of a study of the prevalence ofEhrlichiaandBorreliaspecies in 341 questingIxodes ricinusticks from two locations in southern Norway. The prevalences ofBorrelia burgdorferisensu lato andEhrlichiaspp. were, respectively, 16 and 11.5% at site 1 and 17 and 6% at site 2. Prevalence and species composition ofBorreliaandEhrlichiavaried with location and date of collection. The dominantBorreliaspecies at both sites wasBorrelia afzelii, followed byBorrelia burgdorferisensu stricto.Borrelia gariniiwas found in only a single tick. The dominant member of theEhrlichiagroup was a recently describedEhrlichia-like organism related to the monocytic ehrlichiae. Variants ofEhrlichia phagocytophilaand the agent of human granulocytic ehrlichiosis were also found. The highest prevalences forB. afzelii,B. burgdorferisensu stricto, and theEhrlichia-like organism were observed in May.B. afzeliiwas most prevalent in females, less prevalent in nymphs, and least prevalent in males, while the prevalence ofEhrlichiawas highest in nymphs, lower in females, and least in males. Double infections withB. afzeliiandB. burgdorferisensu stricto and withB. afzeliiand theEhrlichia-like organism were significantly overrepresented. Tick densities were highest in May, when densities of more than 200 ticks/100 m²were observed, and declined during the summer months to densities as low as 20 ticks/100 m². We conclude that estimates of the prevalence of tick-borne bacteria are sensitive to the choice of date and site for collection of ticks. This is the first study of tick-borneBorreliaandEhrlichiain Norway and the lowest reportedB.gariniiprevalence in Northern Europe. The prevalence of theEhrlichia-like organism is described for the first time in questing ticks.

The nucleotide sequences of the chromosomal dihydropteroate synthase (dhps) genes in sulfonamide-susceptible and sulfonamide-resistant strains of Neisseria meningitidis of serogroups A, B and C were determined. The molecular weights and the amino acid sequences showed similarity to those of all other known dihydropteroate synthase polypeptides. Sequence comparison of the N. meningitidis dhps genes indicated horizontal transfer of DNA segments rather than point mutations as the cause for resistance in meningococci. The dhps genes in three of four sulfonamide-resistant meningococci contained identical central regions of 424 bp. Compared with the corresponding genes in susceptible strains, each central region included an insert of 6 bp. In one of the sulfonamide-resistant strains, the dhps gene was similar to the corresponding genes in the sensitive strains in its NH2-terminal and C-terminal parts. Its central region, however, was identical to the corresponding regions of two of the other resistant genes, and thus it could be seen as a hybrid dhps gene. Transformation experiments and mapping of transformed dhps genes indicated the existence of a novel mechanism for the dissemination of sulfonamide resistance in N. meningitidis. The origin of the resistance-mediating segment of the gene is unknown, but hybridization results showed the presence of homologous dhps genes in Neisseria gonorrhoeae and N. lactamica but not in N. subflava or Branhamella catarrhalis.

AIMS--To investigate the integration of human papillomavirus (HPV)16 in 13 HPV16 positive cervical squamous carcinomas. METHODS--Samples were investigated by Southern blot analysis of the Pst I digestion pattern, two-dimensional gel-electrophoresis, and in situ hybridisation. RESULTS--Integration of HPV16 was found in all cases. In 12 biopsy specimens episomal HPV16 DNA and integrated HPV16 DNA were seen. The episomal DNA occurred as dimers and multimers. In situ hybridisation showed that both integrated and episomal HPV16 DNA were present in the same cell in most tumour cell nuclei. CONCLUSIONS--An intact episomal E2 gene is present in most cases of these cervical cancers, and could therefore replace the regulatory function of an integrated defective E2 gene.

Beta-lactam resistance in Haemophilus influenzae due to ftsI mutations causing altered penicillin-binding protein 3 (PBP3) is increasing worldwide. Low-level resistant isolates with the N526K substitution (group II low-rPBP3) predominate in most geographical regions, while high-level resistant isolates with the additional S385T substitution (group III high-rPBP3) are common in Japan and South Korea.