Ultrastructure of human labial salivary glands. I. Acinar secretory cells

The structure of human labial salivary gland acini was studied by light and electron microscopy. Contrary to previous reports, these glands were pure mucous in nature; no serous elements were present. The acinar cells were found in all stages of maturation. Immature cells were characterized by an extensive and highly organized rough-surfaced endoplasmic reticulum. The Golgi complex was extremely prominent, consisting of stacks of flattened cisternae and swarms of small vesicles. Mucous droplets were almost completely absent. As secretory activity progressed, the endoplasmic reticulum involuted, while the Golgi cisternae became distended and formed many vacuoles. In mature mucous cells, the apical cytoplasm was filled with membrane-bounded mucous droplets, and the nucleus was displaced basally. The droplets frequently showed great variation in density from cell to cell, and even within the same cell they sometimes were quite heterogeneous. They were liberated from the acinar cells by an apocrine process, so that droplets with intact limiting membranes were often observed in the acinar lumen. These droplets soon lysed, their contents fusing into streams of mucus. Occasionally during apocrine secretion a mucous cell failed to reconstitute its apical surface, and its entire contents spilled into the acinar lumen. Unusual cytoplasmic inclusions were present in many of the acinar cells. These inclusions, which were surrounded by a single membrane, consisted of lipid droplets closely associated with bundles of fine filaments.     

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.

     

Interspecies exchange of β 2-microglobulin and associated MHC and differentiation antigens

Radiolabeled human ₂-microglobulin (₂m) can bind to mouse histocompatibility (H-2) antigens on the cell surface or to partially purified H-2 antigens in solution. The complexes containing human ₂m and H-2 antigens from C3H (H-2^k) mice could be immunoprecipitated specifically with alloantisera, rabbit anti-H-2 xenoantisera, and with monoclonal H-2-specific antibodies. Specific association with H-2 antigens was also observed with other haplotypes. The only exception was B10.D2 (H-2 ^d ) from which complexes containing human ₂M could only be precipitated with anti-H-2 xenosera. Thus radiolabeled human ₂M can be used as a specific label for mouse H-2 antigens in precipitation and radioimmunoassays. The application of this finding extends to major histocompatibility complex antigens of other species, and to differentiation antigens with primary association with ₂m.Abbreviations used in this paper MHC major histocompatibility complex - ₂m ₂-microglobulin - LcH Lens culinaris hemagglutinin     

A cross sectional survey for B virus antibody in a colony of group housed rhesus macaques

A systematic sampling technique was used in combination with a highly sensitive and specific ELISA to provide unbiased age-specific prevalence estimates of B virus antibody in rhesus monkeys housed in three different outdoor breeding corrals. Among 146 sampled monkeys, 97% of animals 2.5 years and older were seropositive, while only 22% of younger animals were seropositive. Neither gender nor social dominance ranking were predictive of B virus antibody status. The strong age association was not inconsistent with hypothesized venereal transmission of B virus. Improvements in the epidemiologic understanding of B virus are necessary to assist efforts to eradicate this agent from breeding colonies of rhesus monkeys.     

Variability in Halothiobacillus neapolitanus type strain cultures

Numerous microbial species are reported to utilize oxidation and/or reduction of sulfur containing compounds in the energy producing portions of their metabolism Halothiobacillus neapolitanus cultures obtained from different commercial sources appear to display considerable variability in terms of growth rate, carbonate consumption and activity of individual enzymes.     

Infrared microscopy for the study of biological cell monolayers. I. Spectral effects of acetone and formalin fixation

Infrared spectroscopy of biological cell monolayers grown on surfaces is a poorly developed field. This is unfortunate because these monolayers have potential as biological sensors. Here we have used infrared microscopy, in both transmission and transflection geometries, to study air-dried Vero cell monolayers. Using both methods allows one to distinguish sampling artefactual features from real sample spectral features. In transflection experiments, amide I/II absorption bands down-shift 9/4 cm(-1), respectively, relative to the corresponding bands in transmission experiments. In all other spectral regions no pronounced frequency differences in spectral bands in transmission and transflection experiments were observed. Transmission and transflection infrared microscopy were used to obtain infrared spectra for unfixed and acetone- or formalin-fixed Vero cell monolayers. Formalin-fixed monolayers display spectra that are very similar to that obtained using unfixed cells. However, acetone fixation leads to considerable spectral modifications. For unfixed and formalin-fixed monolayers, a distinct band is observed at 1740 cm(-1). This band is absent in spectra obtained using acetone-fixed monolayers. The 1740 cm(-1) band is associated with cellular ester lipids. In support of this hypothesis, two bands at 2925 and 2854 cm(-1) are also found to disappear upon acetone fixation. These bands are associated with C--H modes of the cellular lipids. Acetone fixation also leads to modification of protein amide I and II absorption bands. This may be expected as acetone causes coagulation of soluble cellular proteins. Other spectral changes associated with acetone or formalin fixation in the 1400-800 cm(-1) region are discussed. (c) 2008 Wiley Periodicals, Inc. Biopolymers 89: 921-930, 2008.This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com.     

Systematics and palaeoecology of middle Toarcian Asteroidea (Echinodermata) from the “Seuil du Poitou”, Western France

Complete, articulated starfish fossils are rare. However, more frequently encountered dissociated skeletal elements (ossicles) permit reliable taxonomic identification, making them a valuable data source for diversity estimates. Nearly 300 asteroid ossicles, collected from the middle Toarcian marls in western France can be assigned to five species. Four species and two genera are described: Comptoniaster vrinensis nov. sp. (Goniasteridae), Poncetaster crateri nov. gen. nov. sp. (Stauranderasteridae), Galbaster recurrans nov. gen. nov. sp. (Goniasteridae) and Pentasteria? liasica nov. sp. (Astropectinidae). The known diversity of Early Jurassic asteroids is increased from 12 to 16 species. These taxa illustrate the diversification of crown-group asteroids early in the Jurassic, following the Permo-Triassic crisis. They also reflect bias of the fossil record, and imply the existence of numerous ghost lineages in the evolutionary trees of extant groups. Variation in asteroid diversity across the “Seuil du Poitou” was driven by ecological constraints. The relative frequency (abundance of ossicles and diversity) of goniasterids and stauranderasterids increases in shallower environments. The Benthopectinidae, represented by Plesiastropecten hallovensis, occurred primarily from deep-shelf sediments. Similar ecological patterns are observed for more recent fossil and extant relatives, which further supports the idea of conservative evolution in post-Palaeozoic starfishes since the Early Jurassic.     

Astrocytes as antigen-presenting cells: expression of IL-12/IL-23

Interleukin-12 (IL-12, p70) a heterodimeric cytokine of p40 and p35 subunits, important for Th1-type immune responses, has been attributed a prominent role in multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Recently, the related heterodimeric cytokine, IL-23, composed of the same p40 subunit as IL-12 and a unique p19 subunit, was shown to be involved in Th1 responses and EAE. We investigated whether astrocytes and microglia, CNS cells with antigen-presenting cell (APC) function can present antigen to myelin basic protein (MBP)-reactive T cells, and whether this presentation is blocked with antibodies against IL-12/IL-23p40. Interferon (IFN)-gamma-treated APC induced proliferation of MBP-reactive T cells. Anti-IL-12/IL-23p40 antibodies blocked this proliferation. These results support and extend our previous observation that astrocytes and microglia produce IL-12/IL-23p40. Moreover, we show that stimulated astrocytes and microglia produce biologically active IL-12p70. Because IL-12 and IL-23 share p40, we wanted to determine whether astrocytes also express IL-12p35 and IL-23p19, as microglia were already shown to express them. Astrocytes expressed IL-12p35 mRNA constitutively, and IL-23 p19 after stimulation. Thus, astrocytes, under inflammatory conditions, express all subunits of IL-12/IL-23. Their ability to present antigen to encephalitogenic T cells can be blocked by neutralizing anti-IL-12/IL-23p40 antibodies.     

Serological evidence of alpha herpesvirus infection in sooty mangabeys

Contact between sooty mangabeys (SMs) and a pigtailed macaque prompted the serological screening of SMs for evidence of infection with B virus. Serological tests detected SM antibodies that reacted with B virus polypeptides. Additional testing was performed with sera from SMs with no previous contact with macaques. Results from these tests indicated that 56% (33/59) of the SMs had antibodies that reacted with B virus and SA8. SM antibodies also reacted with herpesvirus papio 2 and to a lesser extent with human alpha herpesviruses (HSV-1 and HSV-2). There was an age-related increase in the presence of these antibodies in SMs that was consistent with the serological pattern of reactivity observed in other nonhuman primate species infected with alpha herpesviruses. These data suggest that SMs may be a host for a herpesvirus that is antigenically similar to those viruses present in other Old World nonhuman primates.