Complex tibial organs in fore-, mid-, and hindlegs of the bushcricket Gampsocleis gratiosa (Tettigoniidae): Comparison of morphology of the organs

The structure of the complex tibial organs in the fore-, mid-, and hindlegs of the East Asian bushcricket Gampsocleis gratiosa (Tettigoniidae, Decticinae) is described comparatively. In each leg the tibial organs consist of three scolopale organs: the subgenual organ, the intermediate organ, and the crista acoustica. Only in the forelegs are the tibial organs differentiated as tympanal organs, and sound transmitting structures (acoustic trachea, tympana, and tympanal covers) are present. The morphology of the tracheae in the mid- and hindlegs is significantly different from that found in the forelegs. The number of scolopidia in the subgenual organ is highest in the midleg and lowest in the foreleg; in the intermediate organ the number is also highest in the midleg, and the fore- and hindleg contain 40% fewer scolopidia. In the crista acoustica, the number of scolopidia decreases from, the fore- to the mid- and hindlegs. The morphology and the dimensions of the scolopidia and the attachment structures within the crista acoustica of the mid- and hindlegs differ strongly from those in the foreleg. The results indicate that, in addition to the presence of a sound transmitting system, the specific differentiations within the crista acoustica are important for the high auditory sensitivity of the tibial organs in the forelegs. © 1994 Wiley-Liss, Inc.

The auditory-vibratory system of the bushcricket Polysarcus denticauda (Phaneropterinae, Tettigoniidae). I. Morphology of the complex tibial organs

The structure of the complex tibial organs in the fore-, mid- and hindlegs of the bushcricket Polysarcus denticauda (Tettigoniidae, Phaneropterinae) is described comparatively. As is common for bushcrickets, in each leg the tibial organs consist of the subgenual and intermediate organs and the crista acustica. Only in the forelegs are sound-transmitting structures present. They consist of the spiracle, acoustic trachea, and two tympana; the latter are not protected by tympanal covers. The tympana in P. denticauda are extremely thick, not only bordering the two tracheal branches to the outside but also forming the outer wall of the hemolymph channel. The morphology of the tracheae in the mid- and hindlegs is significantly different, causing structural differences, especially in dimensions of the hemolymph channel. The number of scolopidia of the crista acustica of the foreleg is extremely high for a bushcricket. Approximately 50 receptor cells were found, about half of them being located in the distal quarter of the long axis of this organ. Some of the receptors are positioned in parallel on the dorsal wall of the anterior tracheal branch. The number, morphology and dimensions of the scolopidia within the crista acustica of the mid- and hindlegs differ significantly from those of the forelegs, decreasing in both legs to eight and seven receptor cells, respectively. Although the dimensions of the subgenual and intermediate organs are considerably larger in the mid- and hindlegs, the number of receptor cells is approximately the same in the different legs, being somewhat higher in both receptor organs than in those of many other bushcricket species studied previously.

Similar structural dimensions in bushcricket auditory organs in spite of different foreleg size: consequences for auditory tuning

The bushcricket species Decticus albifrons, Decticus verrucivorus and Pholidoptera griseoaptera (Tettigoniidae) belong to the same subfamily (Decticinae) but differ significantly in body size. In spite of the great differences in the dimensions of the forelegs, where the auditory organs are located, the most sensitive range of the hearing threshold lies between 6 and 25 kHz in each case. Only in the frequency range from 2 to 5 kHz and above 25 kHz, significant differences are present. The anatomy of the auditory receptor organs was compared quantitatively, using the techniques of semi-thin sectioning and computer-guided morphometry. The overall number of scolopidia and the length of the crista acustica differs in the three species, but the relative distribution of scolopidia along the crista acustica is very similar. Additionally, the scolopidia and their attachment structures (tectorial membrane, dorsal tracheal wall, cap cells) are of equal size at equivalent relative positions along the crista acustica. The results indicate that the constant relations and dimensions of corresponding structures within the cristae acusticae of the three species are responsible for the similarities in the tuning of the auditory thresholds.

Ultrastructural investigations of Candida albicans after in vitro treatment with the new fungicidal agent rilopirox

Candida albicans was maintained in various culture media and incubated with different concentrations of the antifungal agent rilopirox. After fixation, dehydration and embedding in Spurr's medium, the cells were analysed at the ultrastructural level to investigate morphological aspects of the antifungal mode of action of this new hydroxpyridone compound. All untreated or sham-treated control cells exhibited a normal ultrastructural appearance. The cells were surrounded by a multilayered cell wall of typical structure, and the plasmalemma was in close contact with the cell wall. Also, the cell organelles of the protoplast corresponded well with the findings of other authors. After treatment with rilopirox, a variety of ultrastructural changes were seen, and the extent of damage was dependent on the specific culture condition, drug concentration and incubation time. After only 6 h and 1-10 micrograms ml-1 rilopirox, the plasmalemma exhibited elongated invaginations, the number and size of the lipid droplets had increased and greatly enlarged mitochondria containing electron-dense deposits became visible. The vacuolar system was strongly expanded and occupied nearly the whole cell. Exposure to higher concentrations of the antifungal agent and prolonged incubation times resulted in complete cytoplasmic autolysis and membrane breakdown, while the fungal cell wall remained unaffected. After treatment with 0.5% rilopirox suspension gel on agar cultures, the extent of cellular damage was clearly enhanced and included all cell types of a treated yeast colony, i.e. single blastospores and pseudohyphae.

Uptake and accumulation of tritiated uteroglobin by day-6 rabbit blastocysts

Uptake of uteroglobin (UGL) by day-6 rabbit blastocysts and the intracellular fate of this protein were studied by light- and electron-microscopic autoradiography, immunocytochemistry and acid-phosphatase cytochemistry. UGL, labelled with N-succinimidyl-(2-3-3H)-propionate, was administered to embryos in vitro for 25 min to 4 h. The kinetics, determined from light-microscopic autoradiographs, showed a continuous uptake of the labeled protein over a 4-h period of incubation. At the ultrastructural level, increasing numbers of silver grains and an intense UGL immunoreaction in protein vacuoles and crystalloid bodies of trophoblast cells indicated that 3H-UGL had accumulated in these organelles. The presence of crystalloid inclusions in protein vacuoles suggests their origin by a condensation of the protein content, including UGL. Lysosomes containing radioactivity were rarely found, suggesting a very low degradation rate of the 3H-UGL. Protein vacuoles and crystalloid bodies exhibited no acid phosphatase reaction. The enzyme was mainly found outside the basal and lateral cell membranes of trophoblast cells, and on the rough endoplasmic reticulum of endoderm cells.

Uptake of tritiated uteroglobin by the endometrium of the rabbit during peri-implantation

Uteroglobin, labelled with N-succinimidyl-(2-3-3H)-propionate, was applied in vivo for 3 h to pregnant rabbit uteri 7 and 9 days after mating. Light- and electron-microscopic autoradiographs showed that the endometrial epithelium, both ciliated and non-ciliated cells, is able to take up 3H-uteroglobin, however, with differing intensity. Large areas of labelling were found in the luminal epithelium, whereas the glandular epithelium contained fewer silver grains. Moreover, intensively labelled single cells or symplasms occurred in both luminal and glandular epithelium. They were identified as degenerating or dead cells. After internalization by pinocytosis or phagocytosis, the tritiated uteroglobin was observed in multivesicular bodies or in lysosomes with floccular content. Later, radioactivity was either found within residual bodies or distributed throughout the entire epithelium and the subepithelial stroma, i.e., the silver grains could no longer be assigned to specific cell organelles.