A gross anatomical and histo-morphological study of the vagina of the emu (Dromaius novaehollandiae) and ostrich (Struthio camelus)

The present study details anatomical features of the lining of the emu and ostrich vagina, which in birds may impede the forward movement of spermatozoa. Vaginal samples were collected for light and electron microscopy. Samples for light microscopy were fixed in Bouin’s fluid, while samples for electron microscopy were fixed in 3% glutaraldehyde. After fixation the samples were processed routinely. A series of broad annular mucosal folds bearing convoluted primary folds were present in both ratites. The lining of the vaginal folds was a combination of ciliated, non-ciliated, vesicular and mitochondrial cells. The non-ciliated and a few ciliated cells, lining the crypts, contained mucin droplets. The role of the mucus is unclear. The results of the study show a similarity in the gross anatomical and scanning electron microscope features of the vagina in the emu and ostrich. Differences in the cellular composition of the vaginal epithelium were observed at the transmission electron microscope level.

Infundibulomyces: a new genus of coelomycetes from Thailand

The genus Infundibulomyces is proposed for coelomycetous fungi with nidulariaceous-like conidiomata and bipolar appendaged conidia. Infundibulomyces cupulata sp. nov., collected from fallen leaves of Lagerstroemia sp. from Thailand, is described as the type species of the genus. This fungus is illustrated at the light microscope and scanning electron microscope level and compared with other morphologically related taxa. Cupulate conidiomata are uncommon and Infundibulomyces is compared with these.Key words: anamorphic fungi, coelomycete, Infundibulomyces, Thailand, tropical.

Gold Cluster Compounds are Useful Immunoprobes

Immunocytochemistry generally refers to methods directed toward obtaining information on the in situ distribution of antigens in cells and tissues. Immunocytochemical methods can be applied at either the light or electron microscope levels, or both in concert. The detection of antibody recognition of an antigen (i.e., localization of an antigen) relies upon a reporter system. At the light microscope level, enzymes (e.g., horseradish peroxidase) or fluorochromes are the most widely used reporters in immunocytochemistry. At the electron microscope level, particulate probes (e.g., colloidal gold) are the most widely used reporters. However, enzymes and even fluorochromes can be used at the EM level.In this abstract, we discuss our use of gold cluster immunoprobes as the reporter system in both light and electron microscope level immuncytochemistry. These gold cluster immunoprobes, are commercially known as NanogoldTM (NG). These probes are very small with a diameter of 1.4-nm.

Acidic compartments and rhoptry formation in Toxoplasma gondii

DAMP (3-(2,4-dinitroanilino)-3′amino-N-methyldipropylamine), which differentially accumulates in acidic compartments, was used to identify such compartments in Toxoplasma gondii tachyzoites at the electron microscope level. In both free tachyzoites and dividing intracellular parasites the only sites of DAMP accumulation were mature and forming rhoptries. No labelling of other secretory organelles (micronemes and dense granules), the ER, Golgi or any other membrane-bounded organelles or anything resembling a lysosomal system was observed. Labelling of the forming rhoptries was higher and more homogenous than in mature rhoptries in which labelling was confined to the expanded ends of each organelle. The acid pH-dependent accumulation of DAMP in the forming and mature rhoptries was blocked by ammonium chloride and monensin, reagents known to abolish intracellular pH gradients. Estimates of rhoptry pH, based on the level of DAMP accumulation, show that the intralumenal pH of forming rhoptries is more acidic (pH 5·5–3·5) than the mature rhoptries (pH 7·0–5·0).

Tamsiniella labiosa gen. et sp.nov., a new freshwater ascomycete from submerged wood

Investigations into the fungi occurring on wood submerged in freshwater ecosystems have revealed a unique, but characteristic group of fungi. In this paper a new pyrenomycete, Tamsiniella labiosa gen. et sp.nov., is described and illustrated with light, scanning, and transmission electron micrographs. The genus has remarkable short stipitate cylindrical asci with an internal refractive apical ring that are apically truncate and have an external thickening. Ascospores are ellipsoidal-fusiform and surrounded by a mucilaginous sheath. At the transmission electron microscope level, the annulus part of the ascus apical apparatus is differentiated from the inner ascus wall layer and is composed of horizontally oriented, electron-dense fibrillar material. A narrow plug is present in the centre of the apical ring. An electron-dense amorphous region occurs between the outer ascus wall layer and the annulus part of the apical apparatus. The outer ascus wall layer is lacking at the apex. The ultrastructure of the ascus apex differs from those described in the Lasiosphaeriaceae, Sordariaceae, and Xylariaceae.Key words: aquatic fungi, Myelosperma, new genus, transmission electron microscope.

Isolation and Characterization of an Endopolygalacturonase from Cochliobolus sativus and a Cytological Study of Fungal Penetration of Barley

Endopolygalacturonase (EPG) of Cochliobolus sativus was produced in shake culture and purified by high-performance liquid chromatography. The enzyme had a molecular mass of 34,000 Da, an isoelectric point in the range of 9.0 to 9.5, exhibited endo activity, was nongly-cosylated, and was inhibited by polygalacturonase-inhibiting proteins from bean, pear, and tomato. The amino terminus contained a 14 amino acid region homologous to a region at the N terminus of an EPG of C. carbonum. C. sativus EPG-specific monoclonal antibodies (MAbs) were generated. Western blot analysis confirmed the specificity of the antibodies for the EPG and detected the enzyme in an extract from Hordeum vulgare (cv. Golden Promise) leaf segments infected with C. sativus. Using conventional immunogold and enzyme-gold cytochemical methods, homogalacturonan, esterified pectin, and cellulose were localized in healthy and infected barley leaf epidermis at the electron microscope level. Additionally, the leaf cell wall polysaccharides recognized by purified C. sativus EPG were localized at the electron microscope level, using the purified enzyme as a primary cytochemical reagent, followed by a gold-labeled MAb specific for the enzyme. Loss of polygalacturonic acid in the vicinity of the invading pathogen was visualized cytochemically at the electron microscope level. These observations suggest the involvement of EPG during host penetration by the fungus.

Genome replication in early mouse embryos follows a defined temporal and spatial order

The spatial and temporal organisation of replication sites during early mouse embryogenesis was analysed using high resolution confocal and video fluorescence microscopy. The results show that distinct replication patterns occur in the transcriptionally inactive pronuclei of 1-cell embryos as well as in the transcriptionally active nuclei from 2- and 16/32-cell embryos. This indicates that specific chromatin regions are replicated at different times during S-phase and provides the first evidence that mechanisms controlling the temporal and spatial replication of DNA are already present in the haploid pronuclei of the mammalian zygote. Furthermore the data demonstrate that the male and female pronuclei in one-cell embryos replicate their genomes asynchronously. Finally, we observe changes in the dynamics of embryonic genome replication during early development which correlate with gross chromatin structure transitions detected at the electron microscope level. Taken together these results indicate that DNA synthesis in the mouse zygote follows a defined four-dimensional order which may evolve during development and differentiation.