Focus: Microbiome: Distinct Ecological Niche of Anal,Oral, and Cervical Mucosal Microbiomes in Adolescent Women

Human body sites represent ecological niches for microorganisms, each providing variations in microbial exposure, nutrient availability, microbial competition, and host immunological responses. In this study, we investigated the oral, anal, and cervical microbiomes from the same 20 sexually active adolescent females, using culture-independent, next-generation sequencing. DNA from each sample was amplified for the bacterial 16S rRNA gene and sequenced on an Illumina platform using paired-end reads. Across the three anatomical niches, we found significant differences in bacterial community composition and diversity. Overall anal samples were dominated with Prevotella and Bacteriodes, oral samples with Streptococcus and Prevotella, and cervical samples with Lactobacillus. The microbiomes of a few cervical samples clustered with anal samples in weighted principal coordinate analyses, due in part to a higher proportion of Prevotella in those samples. Additionally, cervical samples had the lowest alpha diversity. Our results demonstrate the occurrence of distinct microbial communities across body sites within the same individual.     

Eine Elektrode zur kontinuierlichen Messung des Gelöstsauerstoffs (pO2) in Fermenterkulturen

Zusammenfassung Die Arbeit beschreibt Aufbau und Eigenschaften einer Elektrode zur kontinuierlichen Messung des Sauerstoffpartialdruckes in Fermenterkulturen. Die nach dem polarographischen Prinzip arbeitende Elektrode leitet sich von der Clarkschen Meßanordnung ab. Ihr wesentliches Merkmal ist die Auftrennung in zwei selbständige Bauelemente, einen Membran-tragenden Glasmantel und den Elektroden-tragenden Meßgeber. Der Elektrodenmantel wird gemeinsam mit dem Fermentergefäß autoklaviert, der thermolabile Meßfühler dagegen erst nachträglich eingesetzt. Die Eichung der Elektrode kann vor dem Autoklavieren in einem Spezialgefäß oder danach im Fermentergefäß vorgenommen werden. Der sterilisierbare, in die Kulturlösung hineinragende Elektrodenmantel wird von der Lösung durch eine O₂-permeable, 250 starke Siliconglasgewebemembran abgeschlossen. Zwischen Siliconschicht und der blanken Platinoberfläche der Kathode befindet sich eine weitere, stabilisierende Membran von 12 Stärke (Cellophanfolie). Die Empfindlichkeit der Elektrode beträgt 10^–9 A/mm Hg pO₂ bei 37°C, die Einstellzeit auf 95% des Endwertes 50 sec bei 37°C. Die Abhängigkeit der Messungen von der Turbulenz des Mediums ist zwischen 400 und 1200 UpM Rührergeschwindigkeit zu vernachlässigen. Wiederholtes Autoklavieren der Siliconmembran hat keinen Einfluß auf die Einstellzeiten.

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An electrode for continuous measurement of oxygen tension in fermenter cultures

Summary The paper describes the construction and properties of an electrode for continuous measurement of oxygen tension in fermenter cultures. The equipment is a modified Clark electrode with a cathode of 99,99% pure Pt and a silver anode. It works polarographically. Its most outstanding feature is the subdivision into two separate construction elements: an outer glass-envelope containing a membrane, and a membrane-carrying electrode. The glass-envelope is autoclavable together with the fermenter vessel, whereas the thermolabile electrode must be inserted into the sterilized glass-envelope. The electrode can be calibrated either in a special vessel before autoclaving the glass envelope, or after sterilization in the air-saturated sterile culture medium, before inoculation.The steam resistent glass-envelope, which is immersed in the culture medium, is covered on the lower part with a silicone membrane of 250 thickness which is stabilized by glass fibers. The silicone membrane is separated from the polished Pt cathode by a second stabilizing membrane (cellophane) of 12 thickness, which is part of the electrode. The sensitivity of the electrode is 10^–9 A/mm Hg pO₂ at 37° C. When the oxygen tension is changed from 0 to 100%, the electrode follows this change up to 95% within 50 sec at 37° C. The reading is nearly independent of the agitation of the medium between 400 and 1,200 rpm of the impeller turbine in the culture vessel. Repeated steam-sterilization has no influence on the response time of the electrode.

     

Effect of oxygen binding on the dielectric properties of hemoglobin

The dielectric properties of horse hemoglobin have been investigated in the frequency range for 100 kcps to 15 Mcps at varying degrees of oxygenation. A linear dependence of the specific increment on the degree of oxygenation was found under a variety of experimental conditions, the increment of oxygenated hemoglobin being about 10% larger than that of deoxygenated hemoglobin. A similar difference was obtained with human adult and fetal hemoglobin. No variation of the dielectric parameters as reported by Takashima and Lumry could be detected.     

Elektronenoptische Untersuchungen des Darmtraktes und der peritrophischen Membran von Cladoceren und Conchostracen (Phyllopoda,Crustacea)

Zusammenfassung Vorder- und Mitteldarmtrakt, sowie peritrophische Membranen (PM) vonDaphnia pulex Leydig,Daphnia magna Straus,Leptestheria dahalacensis Rüppell und deren Nauplien wurden elektronenoptisch untersucht. Die Trichtermündung des Vorderdarmes ist bei Leptestherien mit reusenartig in das Mitteldarmlumen ragenden Borsten versehen. Bei Zellen, die eine geringere Elektronendichte als der Mitteldarmzellgrundtyp aufweisen, handelt es sich wahrscheinlich um jugendliche Zellen. Andere Zellen mit geringer Elektronendichte und jeweils zwei freien Cilien kommen nur bei Leptestherien vor. Die PM setzt sich aus dem in den Mikrofibrillen lokalisierten Chitin und aus einer Grundsubstanz zusammen, die vorwiegend aus Mucopolysacchariden und Proteinen besteht. An der PM-Bildung sind alle Mitteldarmzellen beteiligt. Die Einzelfibrillen entstehen möglicherweise durch als OberflÄchenkatalysatoren wirkende Enzyme und sind bei allen Arten in Streuungstextur und Wabentextur mit lumenseitiger Streuungstextur-Unterlagerung angeordnet. BeiL. dahalacensis sind zusÄtzlich Gittertexturen ausgebildet. Wahrscheinlich entstehen aus gestreut verlaufenden, noch plastischen Mikrofibrillen durch überformung an Mikrovilli in Reihe die Gitter- und durch überformung an Mikrovilli in Reihe und auf Lücke die Wabentexturen. Netzmuster können offenbar auch durch sekundÄre Zusammenlagerungen von bereits primÄr ringförmig um die Mikrovillispitzen gebildetes PM-Material entstehen. Bei fehlender Darmfüllung werden zudem bei Leptestherien weder hochgeordnete Fibrillenmuster, noch PM-Hüllen ausgebildet. Das Mitteldarmlumen ist dagegen mit einem Mikrofibrillenfilz ausgefüllt.

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Electron-mikroscope study of the gut and of the peritrophic membrane in cladocera and conchostraca (Phyllopoda, crustacea)

Summary Foregut, midgut and peritrophic membrane (PM) ofDaphnia pulex Leydig,Daphnia magna Straus andLeptestheria dahalacensis Rüppell were studied with the electron microscope. The tubeshaped foregut ofL. dahalacensis has bristles, which rise up trap-like into the lumen of the midgut. Cells with a lower electron density than most of the other midgut cells are probably juvenile cells. Other cells with a lower electron density each with two free cilia, are only to be found inL. dahalacensis. The PM is composed of chitin localised in microfibrils and of another basic substance consisting mainly of protein and mucopolysaccharides which serve as a matrix. All of the midgut cells participate in the formation of the PM. The microfibrils are possibly formed by enzymes acting as surface catalysts. The microfibrils of all Phyllopoda are either arranged in arbitrary directions or in hexagonal networks which always seem to be accompanied by the random type. PMs ofL. dahalacensis can have in addition an orthogonal orientation of fibrils. Perhaps by transformation of arbitrarily arranged, still plastic fibrils at cell surfaces, where microvilli are arranged in rows, an orthogonal texture results, and where the microvilli are arranged in staggered rows, honeycomblike textures are formed. It may be that these patterns also arise through the secondary assemblage of PM-material which was initially arranged in a cyclic fashion around the microvilli-tips. When the intestinal tract is empty, inL. dahalacensis neither highlyordered patterns of fibrils nor PM are formed. Instead, the midgut lumen is filled up with a compressed, disordered mass of microfibrils.

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Liste der Abkürzungen B Basalmembran - Cu Cuticula - CZ Zelle mit Cilien - eM elektronendichtes Material - H hexagonale Fibrillenmuster - M Mitochondrien - Mv Mikrovilli - N Nucleus - PM peritrophische Membran - R PM-Material in Ringform - tw terminal web Gekürzte Fassung einer von der FakultÄt für Bio- und Geowissenschaften der UniversitÄt Karlsruhe genehmigten Dissertation (Schlecht, 1978)     

Molecular composition of the outer membrane of Escherichia coli and the importance of protein-lipopolysaccharide interactions

Whole cells of Escherichia coli strains 0111, K12 and B as well as the ampicillin-resistant mutant K12 D21 and several lipopolysaccharide (LPS) mutants derived from this strain were analyzed for their molar LPS content per mg dry weight. An increase of the LPS concentration in some LPS mutants was substantiated by analyzing isolated cell walls and relating the molar LPS content to the murein subunit as measure of cell surface area. The increase of LPS was paralleled by increasing amounts of phospholipid while the overall protein content in the outer membrane decreased.According to the pattern of major outer membrane proteins in the various strains and the respective LPS structures, protein-LPS interactions are discussed as important requirements for outer membrane assembly and stability.Abbreviations LPS lipopolysaccharide - SDS sodium dodecyl-sulfate Dedicated to Dr. Otto Lüderitz on the occasion of his 60th birthday     

Temperature-dependent incorporation of 4-amino-l-arabinose in lipid A of distinct Gram-negative bacteria

The confirmation at the DNA level of the existence of clonal variants within Escherichia coli O2 and O18 serotypes has been shown by Southern hybridization analysis of restriction endonuclease digested genomic DNA and subsequent probing with contiguous subclones of the E. coli O101 rfb region. The O101 rfb subclones are believed to represent a conserved region of DNA (Heuzenroeder et al. Molec. Microbiol, in press) and identify serotype variants by means of restriction fragment length polymorphisms (RFLP) within homologous DNA of O2 and O18 E. coli. A number of different restriction enzymes have been used singly and in combination to digest the genomic DNA, thereby allowing construction of restriction maps of the region displaying homology to the O101 rfb region subclones. This analysis further substantiates previously defined evolutionary relationships between O2 and O18 E. coli. These simple probes appear to be able to provide the same clonal information as a battery of isoenzyme, outer membrane protein (OMP) and lipopolysaccharide (LPS) analyses.     

Endogenous membrane tumor necrosis factor (TNF) is a potent amplifier of TNF receptor 1-mediated apoptosis

The heat shock protein 90 (Hsp-90) inhibitor, geldanamycin, and the proteasome inhibitor, MG-132, both inhibited tumor necrosis factor receptor 1 (TNF-R1)- but not TRAIL-induced apoptosis in Kym-1 cells, suggesting that TNF-R1-induced cell death is dependent on NF-kappaB activation in this model. Triggering of TNF-R1 by agonistic antibodies led to cell-type specific induction of endogenous TNF and apoptosis, the latter of which was abrogated by neutralizing TNF specific antibodies. TNF-R1-stimulated cells expressed TNF mainly in a cell-associated form, suggesting that the endogenously produced TNF act in its membrane-bound form. Geldanamycin failed to inhibit apoptosis induction by a combination of agonistic TNF-R1- and TNF-R2-specific antibodies, indicating that both TNF receptors co-operate in TNF-R1-triggered apoptosis in Kym-1 cells. Thus, TNF-R1 stimulation can elicit a strong and rapid apoptotic response via induction of membrane TNF and subsequent cooperation of TNF-R1 and TNF-R2. Moreover, we give evidence that this mechanism circumvents the need of the prolonged presence of exogenous soluble TNF for TNF-R1-mediated apoptosis induction.     

Compartmentalization of the yeast meiotic nucleus revealed by analysis of ectopic recombination

As yeast cells enter meiosis, chromosomes move from a centromere-clustered (Rabl) to a telomere-clustered (bouquet) configuration and then to states of progressive homolog pairing where telomeres are more dispersed. It is uncertain at which stage of this process sequences commit to recombine with each other. Previous analyses using recombination between dispersed homologous sequences (ectopic recombination) support the view that, on average, homologs are aligned end to end by the time of commitment to recombination. We have undertaken further analyses incorporating new inserts, chromosome rearrangements, an alternate mode of recombination initiation, and mutants that disrupt nuclear structure or telomere metabolism. Our findings support previous conclusions and reveal that distance from the nearest telomere is an important parameter influencing recombination between dispersed sequences. In general, the farther dispersed sequences are from their nearest telomere, the less likely they are to engage in ectopic recombination. Neither the mode of initiating recombination nor the formation of the bouquet appears to affect this relationship. We suggest that aspects of telomere localization and behavior influence the organization and mobility of chromosomes along their entire length, during a critical period of meiosis I prophase that encompasses the homology search.     

Database model and specification of GermOnline Release 2.0, a cross-species community annotation knowledgebase on germ cell differentiation

GermOnline is a web-accessible relational database that enables life scientists to make a significant and sustained contribution to the annotation of genes relevant for the fields of mitosis, meiosis, germ line development and gametogenesis across species. This novel approach to genome annotation includes a platform for knowledge submission and curation as well as microarray data storage and visualization hosted by a global network of servers. AVAILABILITY: The database is accessible at http://www.germonline.org/. For convenient world-wide access we have set up a network of servers in Europe (http://germonline.unibas.ch/; http://germonline.igh.cnrs.fr/), Japan (http://germonline.biochem.s.u-tokyo.ac.jp/) and USA (http://germonline.yeastgenome.org/). SUPPLEMENTARY INFORMATION: Extended documentation of the database is available through the link 'About GermOnline' at the websites.