Low nitric oxide concentrations in exhaled gas and nasal airways of mammals without paranasal sinuses

To investigatewhether relevant levels of nasal nitric oxide (NO) are produced in theabsence of paranasal sinuses, we studied 17 healthy baboons, mammalswithout any paranasal sinuses. The animals were anesthetized withketamine hydrochloride and breathed spontaneously. While the baboonsbreathed through a face mask (mouths closed) connected to a respirator,NO concentrations in exhaled gas were sampled from the expiratory limband analyzed by chemiluminescence. While the animals were breathingambient air, nasal gas was sampled via a thin plastic tube and analyzed for NO concentrations by chemiluminescence. Mean NO concentration inthe exhaled gas was 1.00 ± 0.59 parts/billion, and NO release was4.28 ± 2.72 nl/min. A NO concentration of 4.79 ± 2.08 parts/billion was found in the nasal gas (NO release: 7.18 ± 3.13 nl/min). An age-dependent increase in nasal NO levelswas not observed. Exhaled and nasal NO concentrations in baboons weremarkedly lower than in mammals with paranasal sinuses, suggesting thatparanasal sinuses might be an anatomic requirement for production ofrelevant nasal NO levels.

     

Phylogenetic placement of environmental sequences using taxonomically reliable databases helps to rigorously assess dinophyte biodiversity in Bavarian lakes (Germany)

1. Reliable determination of organisms is a prerequisite to explore their spatial and temporal occurrence and to study their evolution, ecology, and dispersal. In Europe, Bavaria (Germany) provides an excellent study system for research on the origin and diversification of freshwater organisms including dinophytes, due to the presence of extensive lake districts and ice age river valleys. Bavarian freshwater environments are ecologically diverse and range from deep nutrient-poor mountain lakes to shallow nutrient-rich lakes and ponds.
2. We obtained amplicon sequence data (V4 region of small subunit-rRNA, c. 410 bp long) from environmental samples collected at 11 sites in Upper Bavaria. We found 186 operational taxonomic units (OTUs) associated with Dinophyceae that were further classified by means of a phylogenetic placement approach.
3. The maximum likelihood tree inferred from a well-curated reference alignment comprised a systematically representative set of 251 dinophytes, covering the currently known molecular diversity and OTUs linked to type material if possible. Environmental OTUs were scattered across the reference tree, but accumulated mostly in freshwater lineages, with 79% of OTUs placed in either Apocalathium, Ceratium, or Peridinium, the most frequently encountered taxa in Bavaria based on morphology.
4. Twenty-one Bavarian OTUs showed identical sequences to already known and vouchered accessions, two of which are linked to type material, namely Palatinus apiculatus and Theleodinium calcisporum. Particularly within Peridiniaceae, delimitation of Peridinium species was based on the intraspecific sequence variation.
5. Our approach indicates that high-throughput sequencing of environmental samples is effective for reliable determination of dinophyte species in Bavarian lakes. We further discuss the importance of well-curated reference databases that remain to be developed in the future.

     

INHIBITORY EFFECTS OF MITOGENS ON ADENOIDAL LYMPHOCYTES IN VITRO

Cultures of human adenoidal lymphocytes exposed briefly to either phytohemagglutinin (PHA), Staphylococcus filtrate (Staph-F), concanavalin-A(Con-A), or pokeweed mitogen (PWM) incorporate increased amounts of thymidine earlier than replicate cultures exposed continuously to the mitogens. These effects can begin in the first 24 hr of culture and are seen maximally between 36 and 72 hr. Once a blastogenic response is established, PHA or PWM can diminish that response. Inhibition with PWM requires that the initial stimulation was with this mitogen, while PHA can inhibit blastogenesis to both PHA and PWM-stimulated cells. Because these mitogens can have a paradoxical effect on adenoidal lymphocytes, being capable of both initiating and inhibiting DNA synthesis, this phenomena should be kept in mind when such systems are utilized for the evaluation of antigens and drug effects.     

Urea: An intermediate of aerobic and anaerobic purine degradation in Rhodopseudomonas capsulata

Abstract A mutant strain ( pur ^-) defective in utilization of purines was isolated from Rhodopseudomonas capsulata . In the mutant, the loss of purine utilization correlated with urease deficiency. In contrast to the wild-type strain, the mutant catalyzed release of urea from purines. The nitrogen of the purine ring was completely liberated as urea indicating that the latter compound is an intermediate of the purine degradation pathway in Rps. capsulata . The degradation pattern was identical under aerobic and anaerobic conditions.     

Molecular classification of zebrafish retinal ganglion cells links genes to cell types to behavior

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Elektronenmikroskopische Untersuchung zur Feinstruktur der endotrophen Tabakmykorrhiza

Zusammenfassung 1. Es wurde die Ultrastruktur der endotrophen Tabakmykorrhiza untersucht. 2. Wie bei den meisten obligaten und gewissen nicht obligaten Parasiten wird in dieser Pilz-Wirt-Gemeinschaft bei der Penetration eine Papille gebildet. Wie dort sind die intracellulären Stadien durch eine extrahaustoriale Matrix und extrahaustoriale Membran vom Wirtsprotoplasten getrennt. Der Pilz bildet schließlich Verzweigungen, die sog. Arbuskeln. Der Pilzinhalt wird vom Wirt resorbiert. Als Reste verbleiden die von extrahaustorialem Matrix-Material umgebenen, kompakte Klumpen bildenden Pilzwände im Wirtscytoplasma. 4. Im Arbuskelstadium bildet der Pilz komplette Septen und ist somit wahrscheinlich gegen völlige und schnelle Degeneration geschützt. 5. Als Reaktion auf den Pilzbefall kommt es zu einer Vermehrung des Wirtscytoplasmas und zu einer Akkumulierung von Organellen in der Nachbarschaft des Pilzes.

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Electron microscopy study on the fine structure of the endotrophic mycorrhiza of tobacco

Summary 1. The ultrastructure of the endotrophic mycorrhiza of tobacco was investigated. 2. During penetration of the host wall a papilla is formed as is observed in plants infected with obligate and certain non-obligate parasites. Similarly the intracellular stages of the fungus are separated from host protoplast by an extrahaustorial matrix and extrahaustorial membrane. 3. The fungus finally produces arbuscules (branching of haustoria). The content of the fungus is completely absorbed by the host. The remaining fungal walls form compact clusters in the host cytoplasm, which are surrounded by matrix material. 4. In the arbuscule stage the fungus forms complete septa and probably in this way is protected from complete and quick degeneration by the host. 5. The host reaction to the infection is an increase in host cytoplasm and an accumulation of organelles near the fungus.