Ultrastructural description of rabies virus infection in cultured sensory neurons

Primary cultures were made from adult mouse spinal ganglia for depicting an ultrastructural description of rabies virus (RABV) infection in adult mouse sensory neuron cultures; they were infected with rabies virus for 24, 36, and 48 h. The monolayers were processed for transmission electron microscopy and immunochemistry studies at the end of each period. As previously reported, sensory neurons showed great susceptibility to infection by RABV; however, in none of the periods evaluated were assembled virions observed in the cytoplasm or seen to be associated with the cytoplasmic membrane. Instead, fibril matrices of aggregated ribonucleoprotein were detected in the cytoplasm. When infected culture lysate were inoculated into normal animals via intra-cerebral route it was observed that these animals developed clinical symptoms characteristic of infection and transmission electron microscopy revealed assembled virions in the cerebral cortex and other areas of the brain. Sensory neurons infected in vitro by RABV produced a large amount of unassembled viral ribonucleoprotein. However, this intracellular material was able to produce infection and virions on being intra-cerebrally inoculated. It can thus be suggested that the lack of intracellular assembly in sensory neurons forms part of an efficient dissemination strategy.

Benznidazole biotransformation in rat heart microsomal fraction without observable ultrastructural alterations: comparison to Nifurtimox-induced cardiac effects

Benznidazole (Bz) and Nifurtimox (Nfx) have been used to treat Chagas disease. As recent studies have de-monstrated cardiotoxic effects of Nfx, we attempted to determine whether Bz behaves similarly. Bz reached the heart tissue of male rats after intragastric administration. No cytosolic Bz nitroreductases were detected, although microsomal NADPH-dependent Bz nitroreductase activity was observed, and appeared to be mediated by P450 reductase. No ultrastructurally observable deleterious effects of Bz were detected, in contrast to the overt cardiac effects previously reported for Nfx. In conclusion, when these drugs are used in chagasic patients, Bz may pose a lesser risk to heart function than Nfx when any cardiopathy is present.

The bladder wall under extreme stress condition: ultrastructural observations in a hibernating mammal.

Comparative ultrastructural observations are presented of the distended bladder of a hibernating dormouse (Muscardinus avellanarius) and a relaxed organ taken from an active animal. The distended bladder of the hibernating animal has an extremely thin wall lined with a three-layer urothelium. An osmiophilic coat lines the luminal surface of the urothelium in the hibernating animal, but it is very thin indeed in the specimen from the active dormouse. In the urothelium of the distended bladder, a larger number of fusiform vesicles (FVs, typical structures of the urothelium with asymmetric unit membrane) is found. On the contrary, lysosomes, multivesicular bodies, and interdigitation of plasma membrane between adjacent cells are all more frequent in the relaxed bladder of the active dormouse. Results suggest that hibernating animals can be a useful model for investigating the biology of epithelial cells in the mammalian bladder.

Spontaneous stage differentiation of mouse-virulent Toxoplasma gondii RH parasites in skeletal muscle cells: an ultrastructural evaluation

Although the predilection for Toxoplasma gondii to form cysts in the nervous system and skeletal and heart muscles has been described for more than fifty years, skeletal muscle cells (SkMCs) have not been explored as a host cell type to study the Toxoplasma-host cell interaction and investigate the intracellular development of the parasite. Morphological aspects of the initial events in the Toxoplasma-SkMC interaction were analysed and suggest that there are different processes of protozoan adhesion and invasion and of the subsequent fate of the parasite inside the parasitophorous vacuole (PV). Using scanning electron microscopy,Toxoplasma tachyzoites from the mouse-virulent RH strain were found to be attached to SkMCs by the anterior or posterior region of the body, with or without expansion of the SkMC membrane. This suggests that different types of parasite internalization occurred. Asynchronous multiplication and differentiation of T. gondii were observed. Importantly, intracellular parasites were seen to display high amounts of amylopectin granules in their cytoplasm, indicating that tachyzoites of the RH strain were able to differentiate spontaneously into bradyzoites in SkMCs. This stage conversion occurred in approximately 3% of the PVs. This is particularly intriguing as tachyzoites of virulent Toxoplasma strains are not thought to be prone to cyst formation. We discuss whether biological differences in host cells are crucial to Toxoplasma stage conversion and suggest that important questions concerning the host cell type and its relevance in Toxoplasma differentiation are still unanswered.

Ki-67 MIB1 labelling index and the prognosis of primary TaT1 urothelial cell carcinoma of the bladder.

Aims: To evaluate whether ki-67 labelling index (LI) has independent prognostic value for survival of patients with bladder urothelial tumours graded according to the 2004 World Health Organisation classification. Methods: Ki-67 LI was evaluated in 164 cases using the grid counting method. Non-invasive (stage Ta) tumours were: papilloma (n = 5), papillary urothelial neoplasia of low malignant potential (PUNLMP; n = 26), and low (LG; n = 34) or high grade (HG; n = 15) papillary urothelial carcinoma. Early invasive (stage T1) tumours were: LG (n = 58) and HG (n = 26) carcinoma. Statistical analysis included Fisher and x2 tests, and mean comparisons by ANOVA and t test. Univariate and multivariate survival analyses were performed according to the Kaplan–Meier method with log rank test and Cox’s proportional hazard method. Results: Mean ki-67 LI increased from papilloma to PUNLMP, LG, and HG in stage Ta (p,0.0001) and from LG to HG in stage T1 (p = 0.013) tumours. High tumour proliferation (.13%) was related to greater tumour size (p = 0.036), recurrence (p = 0.036), progression (p = 0.035), survival (p = 0.054), and high p53 accumulation (p = 0.015). Ki-67 LI and tumour size were independent predictors of disease free survival (DFS), but only ki-67 LI was related to progression free survival (PFS). Cancer specific overall survival (OS) was related to ki-67 LI, tumour size, and p27kip1 downregulation. Ki-67 LI was the main independent predictor of DFS (p = 0.0005), PFS (p = 0.0162), and cancer specific OS (p = 00195). Conclusion: Tumour proliferation measured by Ki-67 LI is related to tumour recurrence, stage progression, and is an independent predictor of DFS, PFS, and cancer specific OS in TaT1 bladder urothelial cell carcinoma.

Chemical products : basic guide on labelling and safety data sheets

Hazardous chemical products have to comply with, amongst others, the provisions of a correct classification of danger, labelling and compilation of the safety data sheets. The aim is to protect people's health and the environment from exposure to hazardous chemicals- especially the health and safety of direct users, professionals or not, and the general public, via environmental exposure. This publication is intended to contribute to the knowledge of the objectives and basic aspects of these legal provisions, and thereby increase their degree of compliance in Andalusia and other european regions. This Guide is directed toward those people who, in the development of their professional activities, are in one way or another in contact with dangerous chemical products.

Chemical products : basic guide on labelling and safety data sheets

Hazardous chemical products have to comply with, amongst others, the provisions of a correct classification of danger, labelling and compilation of the safety data sheets. The aim is to protect people's health and the environment from exposure to hazardous chemicals- especially the health and safety of direct users, professionals or not, and the general public, via environmental exposure. This publication is intended to contribute to the knowledge of the objectives and basic aspects of these legal provisions, and thereby increase their degree of compliance in Andalusia and other european regions. This Guide is directed toward those people who, in the development of their professional activities, are in one way or another in contact with dangerous chemical products.

Ultrastructural description of Ceratomyxa microlepis sp. nov. (Phylum Myxozoa): a parasite infecting the gall bladder of Hemiodus microlepis, a freshwater teleost from the Amazon River

A new ceratomyxid parasite was examined for taxonomic identification, upon being found infecting the gall bladder of Hemiodus microlepis (Teleostei: Hemiodontidae), a freshwater teleost collected from the Amazon River, Brazil. Light and transmission electron microscopy revealed elongated crescent-shaped spores constituted by two asymmetrical shell valves united along a straight sutural line, each possessing a lateral projection. The spores body measured 5.2 ± 0.4 µm (n = 25) in length and 35.5 ± 0.9 µm (n = 25) in total thickness. The lateral projections were asymmetric, one measuring 18.1 ± 0.5 µm (n = 25) in thickness and the other measuring 17.5 ± 0.5 µm (n = 25) in thickness. Two equal-sized subspherical polar capsules measuring 2.2 ± 0.3 µm in diameter were located at the same level, each possessing a polar filament with 5-6 coils. The sporoplasm was binucleate. Considering the morphometric data analyzed from the microscopic observations, as well as the host species and its geographical location, this paper describes a new myxosporean species, herein named Ceratomyxa microlepis sp. nov.; therefore representing the first description of a freshwater ceratomyxid from the South American region.

Ultrastructural and molecular analysis of Bowman's layer corneal dystrophies: an epithelial origin?

PURPOSE: Two mutations (R555Q and R124L) in the BIGH3 gene have been described in anterior or Bowman's layer dystrophies (CDB). The clinical, molecular, and ultrastructural findings of five families with CDB was reviewed to determine whether there is a consistent genotype:phenotype correlation. METHODS: Keratoplasty tissue from each patient was examined by light and electron microscopy (LM and EM). DNA was obtained, and exons 4 and 12 of BIGH3 were analyzed by polymerase chain reaction and single-stranded conformation polymorphism/heteroduplex analysis. Abnormally migrating products were analyzed by direct sequencing. RESULTS: In two families with type I CDB (CDBI), the R124L mutation was defined. There were light and ultrastructural features of superficial granular dystrophy and atypical banding of the "rod-shaped bodies" ultrastructurally. Patients from three families with "honeycomb" dystrophy were found to carry the R555Q mutation and had characteristic features of Bowman's dystrophy type II (CDBII). CONCLUSIONS: There is a strong genotype:phenotype correlation among CBDI (R124L) and CDBII (R555Q). LM and EM findings suggest that epithelial abnormalities may underlie the pathology of both conditions. The findings clarify the confusion over classification of the Bowman's layer dystrophies.

Toxicological and ultrastructural analysis of the impact of pesticides used in temperate fruit crops on two populations of Chrysoperla externa (Neuroptera, Chrysopidae)

This study aimed to evaluate the effects of (g a.i. L-1) abamectin (0.02), carbaryl (1.73), sulphur (4.8), fenitrothion (0.75), methidathion (0.4), and trichlorfon (1.5) on the survival of larvae and pupae, on the oviposition of adults and hatching of eggs from treated Chrysoperla externa third-instar larvae from two different populations (Bento Gonçalves and Vacaria, Rio Grande do Sul State, Brazil). Morphological changes caused by abamectin to eggs laid by C. externa from Vacaria population were evaluated by mean of ultrastructural analysis. The pesticides were applied on glass plates. Distilled water was used as control. For the evaluation of larvae mortality, a fully randomized experimental design in a 2 x 7 (two populations x seven treatments) factorial scheme was used, whereas for the effects of the compounds on oviposition capacity and egg viability, a 2 x 4 factorial scheme was used. Carbaryl, fenitrothion, and methidathion caused 100% mortality of larvae. Abamectin reduced the hatching of eggs from treated third-instar larvae of both populations; however, this pesticide presented highest toxicity on insects from Vacaria. The ultrastructural analysis showed that abamectin caused malformations in micropyle and in chorion external surface of C. externa eggs. Based in the total effect (E), carbaryl, fenitrothion, and methidathion are harmful to C. externa; trichlorfon is harmless to third-instar larvae, while abamectin and sulphur are harmless and slightly harmful to third-instar larvae from Bento Gonçalves and Vacaria, respectively.

Chemical labelling of oyster shells used for time-calibrated high-resolution Mg/Ca ratios: A tool for estimation of past seasonal temperature variations

The geochemical compositions of biogenic carbonates are increasingly used for palaeoenvironmental reconstructions. The skeletal delta O-18 temperature relationship is dependent on water salinity, so many recent studies have focused on the Mg/Ca and Sr/Ca ratios because those ratios in water do not change significantly on short time scales. Thus, those elemental ratios are considered to be good palaeotemperature proxies in many biominerals, although their use remains ambiguous in bivalve shells. Here, we present the high-resolution Mg/Ca ratios of two modern species of juvenile and adult oyster shells, Crassostrea gigas and Ostrea edulis. These specimens were grown in controlled conditions for over one year in two different locations. In situ monthly Mn-marking of the shells has been used for day calibration. The daily Mg/Ca.ratios in the shell have been measured with an electron microprobe. The high frequency Mg/Ca variation of all specimens displays good synchronism with lunar cycles, suggesting that tides strongly influence the incorporation of Mg/Ca into the shells. Highly significant correlation coefficients (0.70<R<0.83, p<0.0001) between the Mg/Ca ratios and the seawater temperature are obtained only for juvenile C. gigas samples, while metabolic control of Mg/Ca incorporation and lower shell growth rates preclude the use of the Mg/Ca ratio in adult shells as a palaeothermometer. Data from three juvenile C. gigas shells from the two study sites are selected to establish a relationship: T = 3.77Mg/Ca + 1.88, where T is in degrees C and Mg/Ca in mmol/mol. (c) 2012 Elsevier B.V. All rights reserved.

Ultrastructural data on the life cycle of the parasite, Perkinsus atlanticus (Apicomplexa), on the clam, Ruditapes phillipinarum, in the Mediterranean

An Apicomplexan Perkinsus species has been found parasitizing the clam Ruditapes philippinarum (= Tapes semidecussatus) collected on the Mediterranean coast in the region of the Ebro Delta (Tarragona, Spain). Light and transmission electron microscopy were used to study different stages of this parasite during zoosporulation induced by incubation in thioglycollate medium and seawater. During incubation the trophozoites began zoosporulation, which originated prezoosporangia and zoosporangia at different developmental stages. Successive cytokinesis and nucleokinesis gave rise to prezoospores, which became elongate and differentiated in biflagellated zoospores. The latter presented large mitochondria and an apical complex formed by a conoid, polar ring, micronemes, rhophtries and subpellicular microtubules. The zoosporangium wall showed some typical lamosomes and a discharge tube developed in early phases of incubation. Ultrastructural data were compared with the only four species of the genus Perkinsus previously described. The morphological data, the host and the geographic proximity suggest that the species located on the Mediterranean coast was Perkinsus atlanticus.

Ultrastructural studies of oogenesis in Bolinus brandaris(Gastropoda: Muricidae).

Ultrastructural studies of oogenesis in Bolinus brandaris are described. Although the initial phase of oogenesis is common to most animal species, vitellogenesis can be considered a species-specific characteristic. In the vitellogenesis of B.brandaris, mitochondria and endoplasmic reticula play a relevant role in the formation of myelinised membranous systems. Nuclear envelope, Golgi body and the oocyte plasma membrane invaginations are three possible origins for annulate lamellae. The latter can be considered membranous reservoirs. There are two sources for the vitellum: exogenous (from follicular cells) and endogenous (from the endoplasmic reticulum of the same oocyte).

Ultrastructural and morphometrical analyses of the brown adipocyte nucleus in a hibernating dormouse.

The fine morphology, size, and perichromatin granule frequency were analysed in brown adipocyte nuclei from hibernating, arousing, and euthermic dormice, Muscardinus avellanarius. Unusual nuclear structural constituents such as nuclear amorphous bodies, coiled body-like constituents and bundles of nucleoplasmic filaments were described as typical of hibernating nuclei. Morphometrical findings showed significant difference in total nuclear and nucleolar size in the three physiological conditions investigated as well as decreasing frequency of perichromatin granules in nuclei of hibernating to arousing to euthermic animals. A possible involvement of these granules in the intranuclear transport or storage of pre-mRNA is discussed in the context of other experimental evidence.