[Knowledge of Human Papillomavirus Infection and the Possibilities for Prevention among 13- to 21-Year-Old Students from Fulda, Hessen]. / Kenntnisstand zu Infektionen mit humanen Papillomaviren und deren Präventionsmöglichkeiten von 13- bis 21-jährigen Schülerinnen und Schülern aus Fulda, Hessen.

Study Aim: The aim of this investigation was to assess awareness and knowledge of HPV and HPV vaccination in a sample of female and male students from Fulda. Further vaccination uptake was investigated. Methods: In 2011 a regional cross-sectional survey of 13- to 21-year-old students (n=1 515) was conducted by using a standardised questionnaire. Results: Overall, the awareness and knowledge of human papillomavirus (HPV) was poor. 29% of the sample had heard of HPV. Multivariate analyses demonstrate that females as well as Christians knew HPV better than males and Muslims. Mean HPV knowledge score was 7.8 of 21 (SD=3.3). None of the tested sociodemographic variables was a predictor for better HPV knowledge. 77% of the sample was aware of the HPV vaccination. Females, persons without migration background as well as persons with middle or higher education knew HPV vaccination better than males, persons with migration background and lower educational level. Mean HPV vaccination knowledge score of the female students was 2.9 of 5 (SD=1.3). Older female students had a better level of knowledge than younger ones. 30% of the females had received at least one dose. Higher age, no migration background and middle or higher education status were tested as significant predictors of vaccine uptake. Conclusion: School lessons and consultations would be appropriate places to transfer knowledge in order to prevent health inequalities caused by social determinants.

Methane production in terrestrial arthropods.

We have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. We show that arthropod symbionts can contribute substantially to atmospheric methane.

Effects of temperature, sulfide, and food abundance on growth and feeding of anaerobic ciliates.

The trophic role of ciliates in anaerobic food webs has not been assessed experimentally. In order to obtain basic information necessary to interpret field situations, we studied the effects of temperature, sulfide concentration, and food abundance on the growth and feeding activities of two anaerobic ciliates, Plagiopyla nasuta and Metopus es. The growth rate of P. nasuta increased with temperature from 8 to 18 degrees C (Q(10) = 2.0) and remained constant in the range between 18 and 24 degrees C (0.22 day). Sulfide concentrations of between 0 and 1 mM did not affect the feeding activities, but concentrations greater than 2 mM were inhibitory. The functional response of P. nasuta feeding on fluorescently labeled heterotrophic and phototrophic bacteria was investigated. In both cases, the parameters of the functional response were almost identical when expressed in terms of biovolume: the maximal uptake rate (U(m)) was 1,800 mum ciliate h and the half-saturation constant for ingestion (k) was 1.5 x 10 mum ml. The functional response of M. es feeding on heterotrophic bacteria was found to be similar to that of P. nasuta. These ciliates needed high bacterial abundances in order to maintain their growth (k of about 4 x 10 bacteria ml), implying that they will frequently be food limited in planktonic environments. Both the maximal uptake rates and the maximal clearance rates were comparable to those of aerobic ciliates. By combining the growth and feeding data, we estimated gross growth efficiencies of 12 and 13% for P. nasuta and M. es, respectively. These results indicate that the feeding rates of anaerobic ciliates are similar to those of aerobic ciliates. Their slower growth must, therefore, be due to the lower gross growth efficiency (likely due to anaerobic metabolism).

Symbionts and organelles in ancrobic protozoa and fungi.

The discovery of methanogenic bacteria as endosymbionts of free-living anaerobic protozoa opened new fields of research in microbial ecology, cell physiology and molecular biology. Recent information from 16S rRNA sequence studies has shown in three cases that endosymbiotic methanogenic bacteria differ from free-living species. Frequently, endosymbiotic methanogens are localized in anaerobic protozoa near hydrogenosomes - organelles that produce H2, C02 and acetate, all of which are substrates for methanogenesis. Hydrogenosomes are also present in anaerobic fungi. The current view is that the organelles are endosymbllont-derived and were probably acquired on several distinct occasions during evolution.

Symbiotic association of Psalteriomonas vulgaris n. spec. with Methanobacterium formicicum.

The free-living anaerobic flagellate Psalteriomonas vulgaris n. spec. is described. The organism has four flagella of equal length which arise immediately subapically to the anterior part of the cell, within the apex of the ventral groove. The ultrastructural organization of the mastigont system and the ventral groove show the characteristics of the genus Psalteriomonas. The cells harboured methanogenic endosymbionts which were associated with hydrogenosome-like organelles in which hydrogenase could be localized. The methanogenic bacteria were isolated and identified as Methanobacterium formicicum. After addition of 5% O(2) to the cultures, the cells lost the methanogenic endosymbionts. P. vulgaris lacked cytochrome oxidase and catalase but contained superoxide dismutase.

Axenic cultivation of the anaerobic free-living ciliate Trimyema compressum.

The strain N of Trimyema compressum, an anaerobic free-living ciliate, was cultivated axenically in a medium containing a buffered salt solution, yeast extract, trypticase, and glutathione. Dead bacteria were indispensable as food; a culture of the ciliate together with heat-killed Klebsiella pneumoniae has been established for more than one year. In the medium described, the ciliates grow to a higher cell density than in cultures with living bacteria as food. During the process of axenization, a nonmethanogenic bacterial endosymbiont was lost. In the microbodies of T. compressum, hydrogenase could be localized by the technique of indirect immunofluorescence.

Methanogenic bacteria as endosymbionts of the ciliate Nyctotherus ovalis in the cockroach hindgut.

Production of methane in the hindgut of the cockroach Periplaneta americana was found to vary, depending on the feeding regimen. Methane production was positively correlated with the numbers of the ciliate Nyctotherus ovalis living in the cockroach hindgut. Defaunation of the cockroaches by means of low concentrations of metronidazole (Flagyl) resulted in a quick drop of methane production. Addition of the methanogenic substrates acetate and formate to isolated hindguts stimulated methane production. Inside the ciliate cells, autofluorescing bacteria could be demonstrated which were presumed to be methanogens. Electron microscopy revealed that the bacteria resembled Methanobrevibacter and that they were closely associated with organelles which contained infolded membranes and which were presumably hydrogenosomes.

Effect of fixation on activity and cytochemistry of hydrogenosomal enzymes in Trichomonas vaginalis.

The effect of fixation on the activity of malate dehydrogenase (decarboxylating) and pyruvate synthase was investigated in Trichomonas vaginalis. Subsequently a cytochemical staining method was developed for the demonstration of malate dehydrogenase activity in hydrogenosomes. After fixation of cells in low concentrations of glutaraldehyde and incubation in the presence of malate and the tetrazolium compound 2-(2'-benzothiazolyl)-5-styryl-3-(4'-phthalhydrazidyl)tetrazolium chloride, an electron-dense deposit was produced in the hydrogenosomes. During the whole procedure strictly anaerobic conditions were required. Attempts to develop an analogous procedure for pyruvate synthase failed because even low concentrations of glutaraldehyde strongly inhibited enzyme activity. When cells were fixed in low concentrations of glycolaldehyde and acetaldehyde, a high enzyme activity was retained, but no staining could be achieved. Application of both staining methods to the sapropelic ciliates Trimyema compressum and Plagiopyla nasuta gave negative results.

Psalteriomonas lanterna gen. nov., sp. nov., a free-living amoeboflagellate isolated from freshwater anaerobic sediments.

A novel amoeboflagellate, isolated from anoxic sediment samples, is described and named Psalteriomonas lanterna gen. nov., sp. nov. The cells of the flagellate stage show a fourfold rotational symmetry with four nuclei, four ventral grooves and four mastigont systems. Each mastigont has four flagella of equal length. Microtubular roots, striated roots or rhizoplasts and electron-dense structures are associated with their basal bodies. A Golgi apparatus is absent. Organelles surrounded by rough endoplasmic reticulum (RER) are presumably modified mitochondria. Methanogenic endosymbiotic bacteria are closely associated with microbodies and form a central body. Nuclear division shows the characteristics of a closed mitosis. Cells of the amoeboid stage are mononucleated and lack the methanogenic endosymbionts. Reproduction occurs in both stages of the life cycle.

Hyphal and mycelial interactions betweenAgaricus bisporus andScytalidium thermophilum on agar media.

The interaction betweenAgaricus bisporus andScytalidium thermophilum on agar media was studied by differential interference contrast and phase contrast microscopy.A. bisporus combatively replacesS. thermophilum in culture on agar media. The antagonistic effect ofA. bisporus is transmissible through a cellophane membrane and causes irreversible disintegration ofS. thermophilum protoplasm, resulting in a total loss of viability after prolonged interaction between the two fungi. On compost extract agar, but not on other media, the growth rate ofA. bisporus increased from 2.7 to 5.3 mm·d(-1) following contact withS. thermophilum mycelium.

Symbiosis of protozoa with hydrogen-utilizing methanogens.

The symbiotic interaction between bacteria and protozoa is a well-known phenomenon. Endosymbiosis of bacteria in the amoeba Pelomyxa was reported as early as 1902 by Pénard and since then endosymbiosis has been described for a variety of protozoa by many authors. Also episymbiosis of bacteria and protozoa has been observed frequently. However, surprisingly little is known about the physiological interaction of both partners in such a close association. This is mostly because of problems that arise in characterizing the bacteria, and the unknown nature of excretion products of one partner utilized by the other. The discovery of some unique fluorescent cofactors involved in methane biochemistry which are specific for methanogenic bacteria enabled recognition of these microorganisms by fluorescence microscopy. Using this technique, several symbiotic associations between anaerobic protozoa and methanogenic bacteria have been found. The aim of this paper is to review the field and to discuss the possible functions of symbiosis for both bacteria and protozoa.

Methanogenesis: surprising molecules, microorganisms and ecosystems.

Methanogenesis involves a novel set of coenzymes as one-carbon and electron carriers. Consequently, metabolic processes of methanogens deviate from those present in non-methanogenic bacteria. Methanogenic bacteria can be classified on the basis of substrate utilization. Group I (24 species) grows at the expense of hydrogen plus CO2 and/or formate and group II (7 species) uses methanol and/or acetate. Hydrogen-consuming methanogens are found as epi- or endosymbionts of anaerobic ciliates.

Association of methanogenic bacteria with ovine rumen ciliates.

1. The frequency of association between methanogenic bacteria and ovine rumen ciliates was studied in the rumen fluid of a fistulated sheep. 2. A period of fasting and flushing of the rumen content with nitrogen resulted in a relatively high association, whereas the intake of food and flushing with hydrogen caused a detachment of the methanogenic bacteria from the ciliates. 3. The changes in the frequency of association can be correlated with the relative attribution to the H2 production by hydrogenogenic bacteria and rumen ciliates.

Association of methanogenic bacteria with rumen ciliates.

In 11 species of rumen ciliates belonging to nine genera of the family Ophryoscolecidae (order Entodiniomorphida) an ectosymbiosis with methanogenic bacteria was found. The bacteria could be identified as methanogens on the basis of the presence of specific fluorescent coenzymes (F350 and F420). This somatic interaction may reflect a metabolic interaction in which efficient interspecies hydrogen transfer benefits both partners.

High incidence of sensitivity to yeast killer toxins among Candida and Torulopsis isolates of human origin.

Among yeast strains of human origin belonging to the genera Candida, Cryptococcus, Torulopsis, and Rhodotorula which were examined for killer and sensitive characteristics with killer and sensitive strains of Cryptococcus, Hansenula, Kluyveromyces, Pichia, Saccharomyces, and Torulopsis as screening organisms, a high incidence of sensitivity to killer toxins was observed within the genera Candida and Torulopsis. Of 142 strains tested, 116 strains distributed over all Candida and Torulopsis species examined were sensitive to one or more killers. Several new intergeneric killer-sensitive relationships are described. Furthermore, killing activity was exhibited by six strains of Candida (C. krusei, C. guilliermondii) and three strains of Torulopsis (T. glabrata).

Physiological conditions affecting the sensitivity of Saccharomyces cerevisiae to a Pichia kluyveri killer toxin and energy requirement for toxin action.

The interaction between the killer toxin of Pichia kluyveri 1002 and cells of Saccharomyces cerevisiae SCF 1717 is strongly affected by the physiological state of sensitive cells. The killing effect is maximal for cells in the lag and early exponential phase of growth, whereas stationary cells are completely resistant. Furthermore, sensitivity is markedly enhanced by a rise of the pH (from 3.2 to 6.8) at which cells are cultured. Three successive stages can be distinguished in the killing process: (I) binding of the toxin to the primary binding site; (II) transmission of the toxin to its reactive site in the plasma membrane; (III) occurrence of functional damage (K+-leakage; decrease of intracellular pH). The transition from stage I to II is prevented in the absence of metabolic energy or at low temperature (below 10 degrees C). Sensitive cells in stage I can be rescued from toxin-induced killing by a short incubation at pH 7.0, which treatment is not effective for cells in stage II. Cells in stage II are able to resume growth when plated in a rich medium containing suitable concentrations of potassium and hydrogen ions. Rescue was not observed for cells in stage III of the killing process.

Effects of Pichia kluyveri killer toxin on sensitive cells.

The killer toxin produced by Pichia kluyveri 1002 kills yeast strains of the genera Candida, Saccharomyces and Torulopsis, including several S. cerevisiae killer strains. Binding of a lethal amount of the toxin to cells of S. cerevisiae SCF 1717 occurs rapidly after toxin addition. After treatment with the toxin for 10 min sensitive cells partially recovered when incubated under conditions that favor protein synthesis. Only after a lag time of 50--90 min sensitive cells changed physiologically. Killing of sensitive cells was characterized by leakage of potassium and adenosine 5'-triphosphate, decrease of intracellular pH, and inhibition of the active uptake of amino acids. These effects coincided with cell shrinkage and varied with incubation conditions. Uptake of the amino acid leucine in sensitive cells involved two apparently distinct transport systems (Km1 = 0.04 mM; Km2 = 0.46 mM). The toxin showed different effects on these transport systems.

Production, purification and properties of a Pichia kluyveri killer toxin.

Production of the killer toxin of Pichia kluyveri 1002 was stimulated in the presence of yeast extract. In a minimal medium production was optimal at pH 3.8-4.0 and 22--25 degrees C. Addition of gelatin and nonionic detergents, like Brij-58 (polyoxyethylene 20 cetyl ether) and Triton-X-100, to this medium enhanced production significantly. The killer toxin was purified 140-fold by use of a stepwise ethanol precipitation and butyl Sepharose column chromatography. The purified killer toxin, which still contained some carbohydrates, appeared to be glycoprotein with a mol wt of about 19 000 and an isoelectric point of 4.3. It was stable between pH 2.5 and 4.7 and up to 40 degrees C.

Removal of Escherichia coli in wastewater by activated sludge.

Removal of bacteria from wastewater treated with activated sludge was studied by the use of a streptomycin-resistant Escherichia coli strain. The removal appeared to be a biphasic process. A rapid sorption of bacteria to the sludge flocs took place in the first hour after seeding mixed liquor with E. coli. Thereafter, slower elimination of E. coli was observed. The latter process was due to predation on E. coli by ciliated protozoa. This was shown by: (i) appearance of fluorescent food vacuoles of ciliates when fluorescent E. coli cells were added to mixed liquor; (ii) inhibition of predation either in the presence of cycloheximide or under anaerobic conditions; and (iii) absence of predation in bulking and washed sludge.