Slow-moving soil organisms on a water highway: aquatic dispersal and survival potential of Oribatida and Collembola in running water.

Background: Oribatida and Collembola are an important part of the soil food web and increase soil fertility by contributing to the recycling of nutrients out of dead organic matter. Active locomotion enables only limited dispersal in these tiny, wingless arthropods, while passive dispersal plays an important role for long-distance dispersal. Previous investigations have focused on passive transport by wind, other animals, or sea currents, whereas studies on transport via running water are missing.

VIRMISCO - The Virtual Microscope Slide Collection.

Digitisation allows scientists rapid access to research objects. For transparent to semi-transparent three-dimensional microscopic objects, such as microinvertebrates or small body parts of organisms, available databases are scarce. Most mounting media used for permanent microscope slides deteriorate after some years or decades, eventually leading to total damage and loss of the object.

Respiratory adaptations to a combination of oxygen deprivation and extreme carbon dioxide concentration in nematodes.

To examine physiological adaptations to the two combined stressors O deprivation and extreme CO concentrations, we compared respiratory responses of two nematode species occurring in natural CO springs. The minimum O concentration allowing maintenance of respiration in both species was 0.0176μmol Oml (corresponds to 1.

A reinvestigation of spermiogenesis in Amphilina foliacea (Platyhelminthes: Amphilinidea).

Spermiogenesis in the amphilinidean cestode Amphilina foliacea (Rudolphi, 1819) was examined using transmission electron microscopy. The orthogonal development of the two flagella is followed by a flagellar rotation and their proximodistal fusion with the median cytoplasmic process. This process is accompanied by extension of both the mitochondrion and nucleus into the median cytoplasmic process.

Spermatozoon cytoarchitecture of Amphilina foliacea (Platyhelminthes, Amphilinidea).

The mature spermatozoon of Amphilina foliacea Rudolphi, 1819 has been examined using transmission electron microscopy. The male gamete is filiform and tapered at both extremities. Its moderately electron-dense cytoplasm possesses two parallel axonemes of unequal lengths with the 9 + "1" trepaxonematan pattern, a mitochondrion, a nucleus, parallel cortical microtubules, four electron-dense attachment zones, and electron-dense glycogen granules.

Ultrastructural characteristics of the protonephridial terminal organ and associated ducts of adult specimens of the Aspidogastrea, Digenea and Monogenea, with comments on the relationships between these groups.

Transmission electron microscopical observations were made on the protonephridial terminal organ and associated ducts of three adult trematodes, the aspidogastrean Aspidogaster limacoides Diesing, 1835 and the digeneans Azygia lucii (Müller, 1776) and Phyllodistomum angulatum Linstow, 1907, and the monogenean Ancyrocephalus paradoxus Creplin, 1839. Previously unreported ultrastructural details of the terminal organ of adult trematodes include multiple contact sites (septate junctions and zonulae adherentes) between the membranes of the terminal and adjacent canal cells. Septate junctions traverse the epithelial cytoplasm of the canal wall, and the same type of septate junctions are observed within the cytoplasmic cord at the level of the tip of the flame tuft in both longitudinal and oblique sections of all three trematode species studied.

Ultrastructure of the ovary of Amphilina japonica Goto & Ishii, 1936 (Cestoda) and its implications for phylogenetic studies.

The ultrastructure of the ovary of the amphilinidean cestode Amphilina japonica Goto & Ishii, 1936 from the body-cavity of the American sturgeon Acipenser transmontanus Richardson is described using transmission electron microscopy. The characters of the ovary of Amphilina japonica are different from those of all other cestodes. The most important difference is in the nature of the relationship between the germ and accessory cells within the ovary.

Ultrastructure of the ovarian follicles, oviducts and oocytes of Gyrocotyle urna (Neodermata: Gyrocotylidea).

An ultrastructural study of the ovarian follicles and their associated oviducts of the cestode Gyrocotyle urna Grube et Wagener, 1852, a parasite from the spiral valve of the rabbit fish, Chimaera monstrosa L., was undertaken. Each follicle gives rise to follicular oviduct, which opens into one of the five collecting ducts, through which pass mature oocytes.

Ultrastructure of the neodermal sclerites of Gyrocotyle urna Grube and Wagener, 1852 (Gyrocotylidea, Cestoda).

Body sclerites of Gyrocotyle urna Grube and Wagener, 1852, parasites of Chimaera monstrosa L., were studied by transmission electron microscopy. Each sclerite consists of ten to 15 concentric layers varying in electron density and thickness.

Community assembly of terrestrial testate amoebae: how is the very first beginning characterized?

Testate amoebae play an important role at the very first beginning of succession on land. We used litterbags buried into four different soils to study the early colonization (which occurred within less than 55 days) and establishment of testate amoebae. The litterbag cellulose exposed at the youngest mining site poor in nitrogen and phosphorus was colonized firstly in high abundances, whereas the substrate introduced into the reference sites of undisturbed soil was colonized slowly and in low densities.