Rindenzellen von Federn im Elektronenmikroskop

Zusammenfassung An Querschnitten von Federästen zweier Vögel (Gallus und Pharomacrus) wurden die Rindenzellen im Elektronenmikroskop untersucht. Sie treten in zwei durch übergänge verbundenen Querschnittsformen auf: einerseits stark abgeplattet mit dichtem Keratinmantel und spaltförmigem Intramoenialraum, andererseits unregelmäßig polygonal umrissen mit Zerklüftung der Tonofibrillenmasse Über das ganze Zellareal hin in grobe Bündel. In beiderlei Zellen verlaufen die Tonofibrillen nach der Länge des Federastes, in Übereinstimmung mit der Aussage der Polarisationsoptik. Die Rindenzellen sind mit Membran bekleidet. An den Grenzen sich berührender Zellen erscheint zwischen den beiden Membranen eine Mittellamelle (central component von Filshie u. Rogers, 1962), die als Kittschicht gedeutet wird, welche die Nachbaren zusammenhält. Auf beiden Seiten der Mittellamelle findet sich eine helle Zone von etwa 8 nm Dicke, die bis zur Membran reicht; ihre Deutung ist fraglich. Die geschilderte Zellgrenzstruktur gilt sowohl für den flächigen Kontakt benachbarter Zellen als auch für die Verzahnung längs aufeinanderfolgender. Verzahnung gibt sich am Zellquerschnitt in der Anwesenheit von rundlichen intrazellulären Arealen zu erkennen, die von der Zellgrenzstruktur umschlossen sind; es handelt sich bei ihnen um Querschnitte von Zellfortsätzen, mit denen die eine Zelle in die andere eindringt.Bei beiden untersuchten Formen finden sich luftführende Melaningranula, über deren Bau später berichtet werden soll.     

Electron Microscopy of Peripheral Nerves and Neuromuscular Junctions in the Wasp Leg

The peripheral nerve branch innervating the femoral muscles of the common yellow jacket (Vespula carolina) has been found to possess a thick lemnoblast basement membrane and a complex mesaxon. The term "tunicated nerve" is proposed to designate the type of peripheral nerve in which one or several axons are loosely mantled by meandering, cytoplasm-enclosing membranes of the lemnoblast. The peripheral axon courses longitudinally in a groove in the muscle fiber between the plasma membrane of the muscle fiber and a cap formed by lemnoblast and tracheoblast. The junction is characterized by apposition of plasma membranes of axon and muscle fiber, abundant mitochondria, and synaptic vesicles in the axon, and aggregates of "aposynaptic granules" plus mitochondria and endoplasmic reticulum on the muscle side of the synapse. Unlike the vertebrate striated muscle fiber, no complex infolding of the synapsing plasma membrane of the muscle fiber occurs. The "connecting tissue" of the insect is formed by tracheoblasts, their basement membranes, and the basement membranes of other cells. Further mechanical support is given by the ramifying tracheoles. The physiologic roles of the specialized structures are considered.     

Die Cuticula der Epidermis des Regenwurms (Lumbricus terrestris L.)

Zusammenfassung Die um 3–4 dicke Cuticula des Regenwurms (Lumbricus terrestris L.) besteht aus 20–30 sich annähernd rechtwinklig kreuzenden Lagen von Cuticulafibrillen. Senkrecht zu und zwischen den sich kreuzenden Fibrillen verlaufen röhrenförmige Zellfortsätze, Cuticulakanälchen von der Oberfläche der Epithelzelle zur Epicuticula. Die Epicuticula bildet eine kontinuierliche, mit feinen, dicht stehenden Exkreszenzen besetzte Schicht. Die zelluläre, respektive extrazelluläre Natur der Cuticulastrukturen und ihr funktionelles Verhalten werden besprochen. Anmerkung bei der Korrektur. Die Herren D. Peters (Hamburg) und W. J. Schmidt (Gießen) machten uns auf die Untersuchung der Cuticulastruktur des Regenwurms durch Reed und Rudall (1948) aufmerksam.Die von den englischen Autoren gewonnenen Abdruckpräparate aus verschieden tiefen Schichten der Cuticula stimmen mit den hier gezeigten Schnittpräparaten vorzüglich überein und ergänzen sie durch die Aufsicht auf die freie Oberfläche. Mit der Abdrucktechnik sind jedoch die Cuticula-Kanälchen zwischen den Fibrillen nicht erkannt worden. Einige der Vermutungen über die Bildung der Cuticulafibrulen (s. auch Rudall 1950) dürften deshalb hinfällig geworden sein. Über die chemische Zusammensetzung der Cuticula und ihre chemischen Unterschiede gegenüber Kollagen s. Watson und Smith (1956).Mit dankenswerter Unterstützung durch das Kultusministerium des Landes Nordrhein-Westfalen durchgeführte Untersuchung.     

Campylobacter spp., Giardia spp., Cryptosporidium spp., noroviruses, and indicator organisms in surface water in southwestern Finland, 2000-2001

A total of 139 surface water samples from seven lakes and 15 rivers in southwestern Finland were analyzed during five consecutive seasons from autumn 2000 to autumn 2001 for the presence of various enteropathogens (Campylobacter spp., Giardia spp., Cryptosporidium spp., and noroviruses) and fecal indicators (thermotolerant coliforms, Escherichia coli, Clostridium perfringens, and F-RNA bacteriophages) and for physicochemical parameters (turbidity and temperature); this was the first such systematic study. Altogether, 41.0% (57 of 139) of the samples were positive for at least one of the pathogens; 17.3% were positive for Campylobacter spp. (45.8% of the positive samples contained Campylobacter jejuni, 25.0% contained Campylobacter lari, 4.2% contained Campylobacter coli, and 25.0% contained Campylobacter isolates that were not identified), 13.7% were positive for Giardia spp., 10.1% were positive for Cryptosporidium spp., and 9.4% were positive for noroviruses (23.0% of the positive samples contained genogroup I and 77.0% contained genogroup II). The samples were positive for enteropathogens significantly (P < 0.05) less frequently during the winter season than during the other sampling seasons. No significant differences in the prevalence of enteropathogens were found when rivers and lakes were compared. The presence of thermotolerant coliforms, E. coli, and C. perfringens had significant bivariate nonparametric Spearman's rank order correlation coefficients (P < 0.001) with samples that were positive for one or more of the pathogens analyzed. The absence of these indicators in a logistic regression model was found to have significant predictive value (odds ratios, 1.15 x 10(8), 7.57, and 2.74, respectively; P < 0.05) for a sample that was negative for the pathogens analyzed. There were no significant correlations between counts or count levels for thermotolerant coliforms or E. coli or the presence of F-RNA phages and pathogens in the samples analyzed.     

Simultaneous detection of Cryptosporidium parvum and Giardia in sewage sludge by IC-PCR

AIMS: The aim of this study was to develop a method based on immunomagnetic capture and polymerase chain reaction (IC-PCR assay) for detection of Cryptosporidium parvum and Giardia intestinalis in sewage sludge. METHODS AND RESULTS: The detection limit of the IC-PCR assay for both organisms was 625 oocysts and cysts ml(-1). By hybridization of PCR products the sensitivity could be increased to 125 oocysts and cysts ml(-1). Forty-four sludge samples from 12 wastewater treatment plants were examined. The samples positive for Giardia (9 out of 44) were from eight wastewater plants and the C. parvum genotype 2 samples (3 out of 44) originated from different sewage works. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: IC-PCR offers the possibility to distinguish between Cryptosporidium and Giardia genotypes. This assay can be used to monitor the presence of these organisms in a community and to determine contamination of sludge used as soil amendment.     

Beobachtungen an experimentell im Zellinnern erzeugten Myelinfiguren

Ohne ZusammenfassungVI. Mitteilung über: Die Zellstrukturen des Dünndarmepithels in ihrer Abhängigkeit von der physikalisch-chemischen Beschaffenheit des Darminhalts.Die Befunde an Myelinfiguren wurden zusammen mit Ergebnissen der früheren Mitteilungen unter dem Thema Physico-chemical behavior of inner membrane systems am 4. 9. 1962 auf dem V. Internationalen Kongreß für Elektronenmikroskopie in Philadelphia, USA, vorgetragen.     

Campylobacter spp., Giardia spp., Cryptosporidium spp., Noroviruses, and Indicator Organisms in Surface Water in Southwestern Finland, 2000-2001

A total of 139 surface water samples from seven lakes and 15 rivers in southwestern Finland were analyzed during five consecutive seasons from autumn 2000 to autumn 2001 for the presence of various enteropathogens (Campylobacter spp., Giardia spp., Cryptosporidium spp., and noroviruses) and fecal indicators (thermotolerant coliforms, Escherichia coli, Clostridium perfringens, and F-RNA bacteriophages) and for physicochemical parameters (turbidity and temperature); this was the first such systematic study. Altogether, 41.0% (57 of 139) of the samples were positive for at least one of the pathogens; 17.3% were positive for Campylobacter spp. (45.8% of the positive samples contained Campylobacter jejuni, 25.0% contained Campylobacter lari, 4.2% contained Campylobacter coli, and 25.0% contained Campylobacter isolates that were not identified), 13.7% were positive for Giardia spp., 10.1% were positive for Cryptosporidium spp., and 9.4% were positive for noroviruses (23.0% of the positive samples contained genogroup I and 77.0% contained genogroup II). The samples were positive for enteropathogens significantly (P < 0.05) less frequently during the winter season than during the other sampling seasons. No significant differences in the prevalence of enteropathogens were found when rivers and lakes were compared. The presence of thermotolerant coliforms, E. coli, and C. perfringens had significant bivariate nonparametric Spearman's rank order correlation coefficients (P < 0.001) with samples that were positive for one or more of the pathogens analyzed. The absence of these indicators in a logistic regression model was found to have significant predictive value (odds ratios, 1.15 × 10⁸, 7.57, and 2.74, respectively; P < 0.05) for a sample that was negative for the pathogens analyzed. There were no significant correlations between counts or count levels for thermotolerant coliforms or E. coli or the presence of F-RNA phages and pathogens in the samples analyzed.