Phänologischer Aufruf

Ohne Zusammenfassung     

Oropharyngeal morphology in the basal tortoise Manouria emys emys with comments on form and function of the testudinid tongue

In tetrapods, the ability to ingest food on land is based on certain morphological features of the oropharynx in general and the feeding apparatus in particular. Recent paleoecological studies imply that terrestrial feeding has evolved secondarily in turtles, so they had to meet the morphological oropharyngeal requirements independently to other amniotes. This study is designed to improve our limited knowledge about the oropharyngeal morphology of tortoises by analyzing in detail the oropharynx in Manouria emys emys. Special emphasis is placed on the form and function of the tongue. Even if Manouria is considered a basal member of the only terrestrial turtle clade and was hypothesized to have retained some features reflecting an aquatic ancestry, Manouria shows oropharyngeal characteristics found in more derived testudinids. Accordingly, the oropharyngeal cavity in Manouria is richly structured and the glands are large and complexly organized. The tongue is large and fleshy and bears numerous slender papillae lacking lingual muscles. The hyolingual skeleton is mainly cartilaginous, and the enlarged anterior elements support the tongue and provide insertion sides for the well‐developed lingual muscles, which show striking differences to other reptiles. We conclude that the oropharyngeal design in Manouria differs clearly from semiaquatic and aquatic turtles, as well as from other reptilian sauropsids. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Polyploidy and high environmental tolerance increase the invasive success of plants

Journal of Plant Research - Ploidy level and genome size (GS) could affect the invasive capacity of plants, although these parameters can be contradictory. While small GS seems to favor dispersion,...     

Effects of pressure and temperature of supercritical carbon dioxide on the extraction of triacylglycerols from plant tissue

The rate of extraction of triacylglycerols with supercritical carbon dioxide can be greatly enhanced by raising the pressure of the fluid to 600 bar, or higher, and its temperature to 60°C, or higher. Both the amount of carbon dioxide and the time required for complete extraction are reduced at such high pressures and temperatures.     

Die Begattung bei den VogelmilbenPterodectes Robin (Analgesoidea,Acari)

Zusammenfassung Die Paarung bei den hier untersuchten epizoischen, federnbewohnendenPterodectes bilobatus Rob. undnov. spec. (in litt.) (Proctophyllodidae- Analgesoidea - Acaridiae) wird über eine nicht differenzierbare Partnersuche mit Erkennen und Prüfen der weiblichen Milbe (Prosopon oder Tritonymphe) durch das adulte M?nnchen eingeleitet. Das K?pfchenende der Tibialborste von Beinpaaren I und II des M?nnchens kann einen spezifischen Reizeindruck (chemorezeptorisch) vom kopulationsbereiten Partner vermitteln. Von Kopf-an-Kopf-Stellung ausgehend, klettert das M?nnchen soweit über das Weibchen, bis es imstande ist, seinen Penis zwischen die beiden Caudallappen des Partners hindurch auszuklinken und in den Kopulationsporus auf dessen Bauchseite einzuschieben. Diese Stellung wird durch ein Paar Ringn?pfe im opisthogastrischen Bereich des M?nnchens, welche sich an der hinteren Rückendecke des Partners mittels eines Zylinder-Kolbensystems mit Vakuum festsaugen, w?hrend der Begattungszeit fixiert. Ein Kittsekret, von Saugnapfdrüsen erzeugt, ebnet das wellige Integument, besonders bei der Tritonymphe ein. BeiPterophagus strictus Megn. sind die beiden N?pfe zu einem Tellerknopf umgebildet, der in eine winklig ausgeschnittene Kapsel auf dem Rücken des Weibchens einrasten kann. Diese Elementverbindung ist nur in einer rückl?ufigen Bewegung zu l?sen. Die Samenübertragung beiPterodectes geschieht direkt. Das Sperma wird mittels Penisstilett in die Bursa copulatrix des Weibchens, welche als Porus nach au?en mündet, eingespritzt. Die Ejakulation besorgt ein Pumpensystem aus drei Blasen, die mit rückflu?hindernden Ventilen ausgestattet sind. Die Blasenpumpe erweitert und pre?t zusammen ein endoskeletaler Chitindoppelflügel, an den dorsoventrale und laterade Muskeln ansetzen. Bei dem gezüchtetenPterodectes bilobatus begattet das reife M?nnchen sowohl weibliche Tritonymphen (ohne Ovarien und Uterus) wie adulte Weibchen (mit vollausgebildetem Genitaltrakt) erfolgreich. Erw?gungen im Sinne der Evolution, wonach wegen paarungshinderlicher K?rperendanh?nge geschlechtliche Frühreife im weiblichen Entwicklungsgang (Tritonymphe) und/oder Penisverl?ngerung erzwungen würde, scheitern daran, da? bis jetzt keine phylogenetische Altersbestimmung der Arten innerhalb einer Gattung m?glich ist.

---

Summary The copulation of the epizoic, plumicole mitesPterodectes bilobatus Rob. and an undescribed new species of the same genus, collected from birds on the Galapagos Islands, is performed by external genitalia and a pair of suction devices on the male, and a special copulatory opening on the female. Pairing begins during the normal movements of individuals within a mite population, when the male recognizes sexually receptive females (prosopons or ?-tritonymphs) by a specific, probably ehemoreceptive stimulation, during inspection of other mites of the same species using the specialized tibial setae of legs I and II. Proceeding from a head-to-head position facing the female, the male crawls over the female’s back to a point from which he is able to release his penis between the cleft formed by the two hysterosomal lobes of the female. By a short reverse movement the male then inserts the penis into the copulatory pore of the female, which is situated within a depression on the opisthodorsal region. This suprafeminal-bipolar position is then fixes by a pair of cup-shaped suckers on the opisthogastric region of the male. These accessory genital organs, equipped with piston and cylinder, work like a vacuum pump and suck on the opisthodorsal region of the female throughout the act of copulation. An adhesive substance, produced by a pair of special glands near the suckers and secreted through them, smooths the dorsal integument of the female, which is corrugated during the tritonymphal instar.Plerophagus strictus Megn. has both accessory genital organs modified to a disk-like button oil a short closely-attached stalk. these buttons may fit into a sharply defined capsule on the opisthodorsum of the female prosopon and tritonymph. Such a connection could be separated only by a reverse movement in a given direction. Fecundation in Pterodectes is performed by the stiletto of the penis which ejaculates sperm through the copulatory pore into the tubular bursa copulatiox. Flowing of the spermal liquid requires a system of pumps and appropriate valves composed of three bladders, which become extended and compressed by a pair of endoskeletal chitinous wings to which are attached dorsoventrally and laterally oriented muscles. In the case ofPterodectes bilobatus, a species from which I have bred all instars, the adult male copulates successfully with both female tritonymphs (without ovaries and uterus) and adult females (with well-developed reproductive system); tritonymphs fecundated and then reared in isolation laid eggs from which both sexes hatched; females fecundated in the adult instar also laid heterosexual eggs. Precocity of tritonymphal instars and/or prolongation of adult male’s penis as a consequence of enlarged hysterosomal lobes of the adult females, which represent obstacles for copulation, is impossible to explain in terms of evolutionary significance. Our knowledge about determination of the phylogenetic age of single species within a genus is too insufficient to justify any hypotheses.

     

Biocalcification through time: environmental challenge and cellular response

A concept explaining biocalcification as a form of calcium detoxification is advanced using geochemical and paleontological criteria. The first appearence of calcareous skeletons at the turn of the Precambrian/Cambrian is interpreted as a biotic response to a gradual rise of Ca²⁺ in world ocean resulting in Ca²⁺ stress environments in shelf areas. Periodic appearance in the Phanerozoic record of heavily calcified marine biota, absent or relic in modern seas, suggests considerable temporal fluctuations of calcium concentrations in the ancient ocean. Temporal changes in Ca²⁺ and mineral nutrient contents in the environment can thus be seen as overriding factors in the evolution of organisms.     

A case study of airborne culturable microorganisms in a poultry slaughterhouse in Styria, Austria

According to Council Directive 90/679/EEC on the protection of workers from risks related to exposure to biological agents at work, nature, degree and duration of workers’ exposure to microorganisms must be determined. This directive has already been implemented in waste and wastewater management. The present case study investigates concentration and composition of microorganisms in a poultry slaughterhouse in the State of Styria, Austria. From June to November 2002, measurements were conducted at the sampling sites ‘moving rail’ and ‘gall bladder separation’ using the Andersen six stage viable cascade impactor and the SKC BioSampler. The results of this study were compared with other previous studies which were carried out using the same device (ACFM) and the same measurement methods. At the processing area of the ‘moving rail’, the median concentration of airborne mesophilic bacteria was 1.7×10⁶ CFU/m³ which is 8000 times higher than the background concentration of residential areas (approx. 210 CFU/m³). The airborne microorganisms concentration was 1.7×10⁴ CFU/m³ at composting plants which is 100 times lower than at a workplace of a poultry slaughterhouse. The study shows that poultry slaughterhouse employees are exposed to high concentrations of airborne microorganisms throughout the entire work time without using a respiratory protective device. For the protection of employees against airborne biological agents, relevant measures should be introduced to this field of work.