Diverse microorganisms colonise the different plant-microhabitats, such as rhizosphere and phyllosphere, and play key roles for the host. However, bacteria associated with pollen are poorly investigated, despite its ecological, commercial and medical relevance. Due to structure and nutritive composition, pollen provides a unique microhabitat. Here the bacterial abundance, community structure, diversity and colonization pattern of birch, rye, rapes and autumn crocus pollens were examined, by using cultivation, high-throughput sequencing and microscopy. Cultivated bacteria belonged to Proteobacteria, Actinobacteria and Firmicutes, with remarkable differences at species level between pollen species. High-throughput sequencing of 16S rRNA gene amplicon libraries showed Proteobacteria as the dominant phylum in all pollen species, followed by Actinobacteria, Acidobacteria and Firmicutes. Both plant species and pollination type significant influenced structure and diversity of the pollen microbiota. The insect-pollinated species possessed a more similar microbiota in comparison to the wind-pollinated ones, suggesting a levelling effect by insect vectors. Scanning electron microscopy as well as fluorescent in situ hybridisation coupled with confocal laser scanning microscopy (FISH-CLSM) indicated the tectum surface as the preferred niche of bacterial colonisation. This work is the most comprehensive study of pollen microbiology, and strongly increases our knowledge on one of the less investigated plant-microhabitats.

Flower pollen represents a unique microbial habitat, however the factors driving microbial assemblages and microbe-microbe interactions remain largely unexplored. Here we compared the structure and diversity of the bacterial-fungal microbiome between eight different pollen species (four wind-pollinated and four insect-pollinated) from close geographical locations, using high-throughput sequencing of the 16S the rRNA gene fragment (bacteria) and the internal transcribed spacer 2 (ITS2, fungi). Proteobacteria and Ascomycota were the most abundant bacterial and fungal phyla, respectively. Pseudomonas (bacterial) and Cladosporium (fungal) were the most abundant genera. Both bacterial and fungal microbiota were significantly influenced by plant species and pollination type, but showed a core microbiome consisting of 12 bacterial and 33 fungal genera. Co-occurrence analysis highlighted significant inter- and intra-kingdom interactions, and the interaction network was shaped by four bacterial hub taxa: Methylobacterium (two OTUs), Friedmanniella and Rosenbergiella. Rosenbergiella prevailed in insect-pollinated pollen and was negatively correlated with the other hubs, indicating habitat complementarity. Inter-kingdom co-occurrence showed a predominant effect of fungal on bacterial taxa. This study enhances our basic knowledge of pollen microbiota, and poses the basis for further inter- and intra-kingdom interaction studies in the plant reproductive organs.

Electrostatically stabilized aqueous dispersions of nm-sized free lipid A particles at low volume fractions (1.0×10−4⩽∅⩽3.5×10−4) in the presence of 1.0–10.0 mM NaCl (25 °C) have been characterized by static and quasielastic light scattering (QELS) techniques, electron microscopy (SEM and TEM), conductivity measurements, and acid–base titrations. QELS and electron microscopy (ρ̄TEM=8.0±0.6%) yield similar values for the particle size and particle size distribution (ρ̄QELS=10.9±0.75 %), whereas conductivity and acid–base titrations estimate surface chemical parameters (dissociation constant, ionizable sites, and Stern capacitance). Effective particle charges were determined by fits of the integral equation calculations of the polydisperse static structure factor, S̄(Q), to the light scattering data. Using the particle properties as determined from these experiments, the polydisperse structure factor, S̄(Q), was calculated as a function of volume fraction, ∅, which was found to be consistent with a S̄(Q) dependence on the number particle density. It can be concluded that, at low volume fractions and low ionic strength, the light scattering data are well represented by a Poisson–Boltzmann model (PBC) of fluid-like ordering of free lipid A in aqueous solution. We find that the light scattering data of this dispersion are best described by a model where only a small fraction of the ionizable phosphate groups is dissociated at neutral pH. Finally, light scattering studies of lipid A dispersions of volume fractions of 3.9×10−4⩽∅⩽4.9×10−4 indicate the presence of long-range order, resulting in distinct peaks which can be assigned either to a face-centered cubic (fcc) lattice (a=51.7 nm) or a body-centered cubic (bcc) lattice (a=41.5 nm), respectively.

BackroundVaginitis is among the most common conditions women are seeking medical care for. Although these infections can easily be treated, the relapse rate is high. This may be due to inadequate use of the diagnostic potential.MethodsWe evaluated the misjudgement rate of the aetiology of vaginal complaints. A total of 220 vaginal samples from women with a vaginal complaint were obtained and analysed for numbers of total lactobacilli, H2O2-producing lactobacilli, total aerobic cell counts and total anaerobic cell counts including bifidobacteria, Bacteroides spp., Prevotella spp. Additionally, the presence of Atopobium vaginae, Gardnerella vaginalis, Candida spp. and Trichomonas vaginalis was evaluated by DNA-hybridisation using the PCR and Affirm VPIII Microbial Identification Test, respectively.ResultsThe participating physicians diagnosed Bacterial vaginosis (BV) as origin of discomfort in 80 cases, candidiasis in 109 cases and mixed infections in 8 cases. However, a present BV, defined as lack of H2O2-lactobacilli, presence of marker organisms, such as G. vaginalis, Bacteroides spp. or Atopobium vaginae, and an elevated pH were identified in only 45 cases of the women examined. Candida spp. were detected in 46 cases. Interestingly, an elevated pH corresponded solely to the presence of Atopobium vaginae, which was detected in 11 cases.ConclusionErrors in the diagnosis of BV and candida vulvovaginitis (CV) were high. Interestingly, the cases of misjudgement of CV (77%) were more numerous than that of BV (61%). The use of Amsel criteria or microscopy did not reduce the number of misinterpretations. The study reveals that the misdiagnosis of vaginal complaints is rather high.

A double-blind, placebo-controlled multicenter study in 157 patients with chronic recurrent sinusitis investigated the occurrence of acute relapses during treatment of patients with a bacterial immunostimulant (3 x 30 drops/day), comprised of cells and autolysate of human Enterococcus faecalis bacteria (Symbioflor 1, n = 78) in comparison to placebo (n = 79). The study included a treatment period of 6 months and a follow-up period of 8 months. Under verum the occurrence of relapses (50 incidents) was about half (56%) the number observed under placebo (90 incidents). In the Kaplan-Meier test the verum preparation emerged as significantly superior (p = 0.045, log rank test) compared to placebo. This superiority of verum was found during the treatment period with 17 vs. 33 relapses (p = 0.019) as well as during the follow-up observation with 33 vs. 57 relapses (p = 0.013). The time interval to the first relapse was clearly longer under verum (513 days) than under placebo (311 days). The relative risk for a relapse under the test preparation compared to placebo was 49.0% during the treatment and 55.8% during the follow-up period. Severity of the acute relapses was comparable in both groups. However, antibiotic therapy was only required in 2 patients treated with verum compared to 6 patients in the placebo group. Both preparations were well tolerated and serious side effects did not occur in either group. No changes in laboratory tests--hematology and clinical chemistry--were observed. Potential immunomodifying effects of the test preparation in view of the significant reduction in relapses were discussed.