Nano-imaging trace elements at organelle levels in substantia nigra overexpressing α-synuclein to model Parkinson’s disease

Sub-cellular trace element quantifications of nano-heterogeneities in brain tissues offer unprecedented ways to explore at elemental level the interplay between cellular compartments in neurodegenerative pathologies. We designed a quasi-correlative method for analytical nanoimaging of the substantia nigra, based on transmission electron microscopy and synchrotron X-ray fluorescence. It combines ultrastructural identifications of cellular compartments and trace element nanoimaging near detection limits, for increased signal-to-noise ratios. Elemental composition of different organelles is compared to cytoplasmic and nuclear compartments in dopaminergic neurons of rat substantia nigra. They exhibit 150–460 ppm of Fe, with P/Zn/Fe-rich nucleoli in a P/S-depleted nuclear matrix and Ca-rich rough endoplasmic reticula. Cytoplasm analysis displays sub-micron Fe/S-rich granules, including lipofuscin. Following AAV-mediated overexpression of α-synuclein protein associated with Parkinson’s disease, these granules shift towards higher Fe concentrations. This effect advocates for metal (Fe) dyshomeostasis in discrete cytoplasmic regions, illustrating the use of this method to explore neuronal dysfunction in brain diseases.

Structure of the Leydig Cell in the African Sideneck Turtle (Pelusios castaneus)

The African sideneck turtle (Pelusios castaneus) is a freshwater turtle of West African origin used in traditional medicine with little consumption as meat. There have been documentations on the reproductive biology of the turtle with no report on the structure of the Leydig cell of the animal. We described the structure of the Leydig cell of the adult African sideneck turtle using histology, microstereology and transmission electron microscopy. The Leydig cell of the African sideneck turtle were elliptical in shape when found proximal to blood vessels and elongated at other points within the testicular interstitium. Leydig cells occurred in cords or clusters of varying sizes and numbers (3-5 cells) that appear to be random in distribution possessing round to ovoid nuclei containing small amount of peripherally disposed heterochromatin with prominent nucleoli. The seminiferous tubules of the turtle occupied about 85% of the total testicular parenchyma while the interstitium occupied 15% of it. Of this 15%, the Leydig cell occupied about 10% while the stromal elements, inclusive of blood vessels occupied the remaining 5%. The cytoplasm of the Leydig cell was about 85% of the entire cell and comprised microfilaments, lipid droplets, smooth and rough endoplasmic reticula as well as numerous mitochondria. In conclusion, the histological and ultrastructural features of the Leydig cell of the African sideneck turtle bear close similarities with those of other reptiles with little variations. These variations include interstitial location as well as in relation to blood vessels within the testicular interstitium. Information made available by this study is expected to be useful in the comparative anatomy of the Leydig cell of turtles and reptiles.

Effects of High Hydrostatic Pressure Processing on the Number of Bacteria and Texture of Beef Liver

Providing beef liver for raw consumption was banned in Japan on July 1, 2012. To lift the ban, the establishment of effective countermeasures for safe raw consumption is necessary. In this study, we examined the effects of high hydrostatic pressure processing on raw beef liver. Beef liver samples subjected to 300 MPa of pressure or higher for 10 min at 25°C became firmer and showed a paler color and were considered unsuitable for raw consumption. More than 3.0 log reductions of bacteria were seen after treatments at 400 and 500 MPa, but the treatment with lower pressure did not show enough microcidal effects for safe consumption. Histological and ultrastructural analysis revealed that high hydrostatic pressure processing increased mitochondrial swelling and reduced rough endoplasmic reticula in hepatocytes, and such changes might be related to the observed changes of texture in the treated raw beef liver.

Eukaryotic origins

The origin of the eukaryotes is a fundamental scientific question that for over 30 years has generated a spirited debate between the competing Archaea (or three domains) tree and the eocyte tree. As eukaryotes ourselves, humans have a personal interest in our origins. Eukaryotes contain their defining organelle, the nucleus, after which they are named. They have a complex evolutionary history, over time acquiring multiple organelles, including mitochondria, chloroplasts, smooth and rough endoplasmic reticula, and other organelles all of which may hint at their origins. It is the evolutionary history of the nucleus and their other organelles that have intrigued molecular evolutionists, myself included, for the past 30 years and which continues to hold our interest as increasingly compelling evidence favours the eocyte tree. As with any orthodoxy, it takes time to embrace new concepts and techniques.

Nucleolus-like bodies in the pineal gland of the adult yak (Bos grunniens)

The pineal glands of adult yak were studied electron microscopically. Nucleolus-like bodies (NLBs) were found mostly in the pinealocytes and the interstitial cells of the pineal glands of the yak. The NLBs were electron-dense, round or ovoid bodies with a diameter of 50 nm – 500 nm. Two types of granules were identified as melanin. These may correspond to different stages of a progressive storage of melanin. Rough endoplasmic reticula with abundant ribosomes were observed. There was no correlation between the number of NLBs and the sex of the animals.

Activity of 2′, 3′-Cyclic Nucleotide 3′-Phosphodiesterase (CNPase) in Spinal Cord with Spongy Change Induced by a Single Oral Dose of Aniline in Rats

A spongy change in the spinal cord white matter was observed in four-week-old rats treated with aniline. Although this change was found to be a result of the myelin sheath splitting at the ultrastructural level, the mechanism is unknown. This study was conducted to identify the mechanism of the spongy change in aniline-treated rats. The spongy change in the spinal cord white matter was first detected on day 5 in the histopathologic examination. The incidence and severity of the lesions, especially in the lateral and ventral funiculi of the thoracic spinal cord white matter, increased prominently from day 8 to day 10. In all rats, immunohistochemical staining by anti-2′, 3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) occurred along the cytoplasmic boundaries of the normal oligodendroglia. However, mild to moderate anti-CNPase staining extended to the swollen cytoplasm of the oligodendroglia in the aniline-treated rats from day 2 to day 4. In the electron microscopic examination, free ribosomes and rough endoplasmic reticula in the cytoplasm of the oligodendroglia increased on days 3 and 4. These changes were considered to be related to CNPase expression. However, CNPase expression decreased, whereas the spongy changes were detected from day 5. The reduction in CNPase expression may contribute to the changes in the myelin morphology observed in aniline intoxication.

Fine structural observation on the oogenesis and vitellogenesis of the Chinese soft-shelled turtle (Pelodiseus sinensis)

SummaryFine structure observations were performed by means of electron microscopy on oogenesis and vitellogenesis and the special functions of follicular cells in the Chinese soft-shelled turtle (Pelodiseus sinensis). Histological examination of the ovary showed a well developed lacunae system containing fine granules, fibres or gelatiniform materials with one or two germinal beds dispersed on the dorsal surface of the ovarian cortex. The process of oogenesis comprised 10 consecutive phases according to the morphology of the yolk platelets, follicular cells and zona pellucida (ZP). Electron microscopy of vitellogenesis revealed some of the mitochondria gradually being transformed into yolk granules. In the advanced stage of vitellogenesis, large amounts of rough endoplasmic reticula, Golgiosomes and other cell organelles that are involved in synthesis and secretion were observed in follicular cells. The ZP was formed by microvilli, thus increasing the absorptive surface of the oocyte and facilitating transport of nutrients from the follicular epithelium to the ooplasm. This study demonstrated that the ovaries of members of the Testudinidae share more features with Archosaurs than with Squamates, indicating that these features were phylogenetically conserved in the Archosauria. The present observations suggest that the accumulation of yolk materials was controlled by the intrinsic and extrinsic pathways as well as by the activity of follicular cells. These results might also support a sibling relationship of the Testudinidae with the Archosauria and not with all extant reptiles.

Ultrastructural changes in female hepatocytes during ovarian maturation of Steindachnerina insculpta (Pisces: Curimatidae)

During gonadal maturation the females of Steindachnerina insculpta, a teleost of the Furnas reservoir, Minas Gerais, Brazil, show low hepatosomatic and high gonadossomatic indexes, suggesting possible transference of hepatic substances to the ovaries. In comparison to the resting phase, in the maturation/mature one the hepatocytes show greater development of both smooth and rough endoplasmic reticula, increased electron density in the mitochondria, and glycogen scattered throughout the cytoplasm. In both resting and maturation/mature phases, the hepatic parenchyma contains melanomacrophagic centers that consist of degenerating cellular debris and are surrounded by capsules formed by cells, resembling fibroblasts, joined by desmosomes. No physiological relation of these centers with ovarian maturation was found.

Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus

The histology and ultrastructure of the hepatopancreas of the Mozambique tilapia O. mossambicus are described. The liver is surrounded by a thin connective tissue capsule. The hepatocyte arrangement shows as lobules, with the hepatocyte cords that radiate and anastomose from a central vein. Borders of individual liver lobules do not show clearly, as do the few triads found in the liver of O. mossambicus. Each hepatocyte contains a single round nucleus with a prominent nucleolus. The rough endoplasmic reticulum appears in two or more rows around the nuclei and in close proximity to the plastnalemma of the hepatocytes. The remaining cytoplasmic organelles are scattered throughout the hepatocyte cytoplasm. The exocrine pancreas cells are centred around the portal veins. The nuclei of these cells are spherical and hasally situated in the cubiform to cylindriform cells. Well developed rough endoplasmic reticula - vesicular, tubular and circular in appearance - as well as secretory granules, apically situated in the cells, are present.

Production and characterization of a novel monoclonal antibody against neurotensin: immunohistochemical localization in the midbrain and hypothalamus.

We developed a mouse monoclonal antibody against neurotensin (NT), termed NT8, for applications in immunohistochemistry and for ELISA analysis of NT. The antibody's paratope was determined by competitive ELISA using several peptide fragments of NT. That paratope requires intact peptide bonds between NT residues proline-7, arginine-8, and arginine-9. The antibody is of the IgG2B sub-isotype, having an IC50 for intact NT of approximately 3 nM when measured by competitive ELISA. Light microscopic immunohistochemical studies in the periaqueductal gray (PAG) and hypothalamus demonstrated staining patterns that agreed well with previous reports. Neuron perikarya were visualized even in the absence of colchicine pre-treatment, indicating that NT8 antibody is very sensitive in immunohistochemical applications. At the EM level, the antibody stained axon terminals, dendrites, and perikarya in the PAG. In lightly immunoreactive perikarya, rough endoplasmic reticula were visualized, suggesting that biosynthetic precursors to NT might be recognized by NT8.