Thorium induced testicular changes in rats.

Daily intraperitoneal administration of thorium nitrate produced progressive morphological and biochemical alterations with the increase in thorium concentration in rat testis. The degenerative changes in the seminiferous tubules increased with the duration of treatment and after 90 days calcification occurred in about 25% of the tubules and in the connective tissue of the tunica albuginea. The activity of adenosine triphosphatase and alkaline phosphatase increased markedly as a result of thorium administration. An attempt has been made to interrelate histopathological and enzymatic changes and the metal concentration in the testicular tissue.     

Ascorbic acid levels in the proglottides of four species of cestode parasites of mammals and birds in relation to their sexual maturity

Ascorbic acid levels were found to be closely related to different stages of growth and maturity of Avitellina centripunctata, Moniezia expansa, and Stilesia globipunctata from goats and sheep and of Raillietina echinobothrida from fowl. The ascorbic acid level in avian parasites was higher than that in mammalian. The level was highest in immature proglottides and lowest in gravid proglottides.     

Fine-scale mapping of physicochemical and microbial landscapes of the coral skeleton

The coral skeleton harbours a diverse community of bacteria and microeukaryotes exposed to light, O₂ and pH gradients, but how such physicochemical gradients affect the coral skeleton microbiome remains unclear. In this study, we employed chemical imaging of O₂ and pH, hyperspectral reflectance imaging and spatially resolved taxonomic and inferred functional microbiome characterization to explore links between the skeleton microenvironment and microbiome in the reef-building corals Porites lutea and Paragoniastrea benhami. The physicochemical environment was more stable in the deep skeleton, and the diversity and evenness of the bacterial community increased with skeletal depth, suggesting that the microbiome was stratified along the physicochemical gradients. The bulk of the coral skeleton was in a low O₂ habitat, whereas pH varied from pH 6–9 with depth. Physicochemical gradients of O₂ and pH of the coral skeleton explained the β-diversity of the bacterial communities, and skeletal layers that showed O₂ peaks had a higher relative abundance of endolithic algae, reflecting a link between the abiotic environment and the microbiome composition. Our study links the physicochemical, microbial and functional landscapes of the coral skeleton and provides new insights into the involvement of skeletal microbes in the coral holobiont metabolism.     

Identification,purification and characterization of a receptor for dengue virus-induced macrophage cytotoxin (CF2) from murine T cells

Dengue type-2 virus infection in mice induces a subpopulation of T lymphocytes to produce a cytokine cytotoxic factor, which induces macrophages (Mphi) to produce a biologically active cytotoxic cytokine, the Mphi cytotoxin (CF2). Previously we have identified the presence of intermediate-affinity receptors for CF2 on mouse peritoneal Mphi. The present study was undertaken to identify the CF2-receptors (CF2-R) on murine T cells followed by their purification and characterization. Receptor binding assay and Scatchard analysis revealed single, high-affinity (1.0309 nM) receptors for CF2 on T cells (22000 receptors per cell). The binding of [125I]CF2 on murine T cells was saturable and specific. Furthermore, CF2-R was purified from normal mouse T cell plasma membrane by affinity chromatography followed by reversed-phase high-pressure liquid chromatography. The presence of CF2-R was confirmed by indirect dot-blot assay and its binding with [125I]CF2. The purified CF2-R is a 90-95-kDa protein as characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis. The chemical crosslinking of [125I]CF2 and its receptor complex showed a product of 100-110 kDa on different subpopulations of murine T cells. The pretreatment of target cells with anti-CF2-R antisera inhibited the cytotoxic activity of CF2 in a dose-dependent manner and thus confirmed the biological significance of CF2-R. Moreover, the presence of CF2-R was also identified on normal human peripheral blood mononuclear cells and T and B cells by crosslinking with [125I]CF2, thus revealing the possible role of CF2 and CF2-R in the immunopathogenesis of dengue virus disease.     

The levels of mature glycosylated nicastrin are regulated and correlate with gamma-secretase processing of amyloid beta-precursor protein

Nicastrin, a type-I transmembrane glycoprotein, is a necessary component of the high molecular weight presenilin (PS) complexes that mediate intramembranous cleavage of beta-amyloid precursor protein (betaAPP) and Notch. Nicastrin undergoes trafficking-dependent glycosylation maturation, and PS1 interacts preferentially with these maturely glycosylated forms of nicastrin. We investigated the effects of differing levels of the immature and mature endoglycosidase-H-resistant forms of nicastrin on Abeta40- and Abeta42-peptide secretion in several cell lines stably expressing a mutant nicastrin (D336A/Y337A) that increases Abeta secretion. There was no correlation between Abeta secretion and the level of over-expression of the immature forms of nicastrin. The total level of mature nicastrin remained constant, but mutant nicastrin replaced endogenous mature nicastrin in varying degrees. Differences in the levels of mature mutant nicastrin positively correlated with Abeta secretion, but did not influence either betaAPP trafficking or processing by alpha- and beta-secretases. Proper trafficking and terminal maturation of nicastrin is therefore a necessary event for the regulated intramembranous proteolysis of betaAPP.     

Development of a new vitrification solution, VSL, and its application to the cryopreservation of gentian axillary buds

Vitrification methods are convenient for cryopreserving plant specimens, as the specimens are plunged directly into liquid nitrogen (LN) from ambient temperatures. However, tissues and species with poor survival are still not uncommon. The development of vitrification solutions with high survival that cover a range of materials is important. We attempted to develop new vitrification solutions using bromegrass cells and found that VSL, comprising 20% (w/v) glycerol, 30% (w/v) ethylene glycol, 5% (w/v) sucrose, 10% (w/v) DMSO and 10 mM CaCl₂, gave the highest survival following cryopreservation, as determined by fluorescein diacetate staining. However, the cryopreserved cells showed little regrowth, for unknown reasons. To check its applicability, VSL was used to cryopreserve gentian axillary buds and the performance was compared with those of conventional vitrification solutions. Excised gentian stem segments with axillary buds (shoot apices) were two-step precultured with sucrose to induce osmotic tolerance prior to cryopreservation. Gentian axillary buds cryopreserved using VSL following the appropriate preculturing approach exhibited 78% survival (determined by the regrowth capacity), which was comparable to PVS2 and PVS1 and far better than PVS3. VSL had a wider optimal incubation time (20–45 min) than PVS2 and was more suitable for cryopreserving gentian buds. The optimal duration of the first step of the preculture was 7–11 days, and preculturing with sucrose and glucose gave a much higher survival than fructose and maltose. VSL was able to vitrify during cooling to LN temperatures, as glass transition and devitrification points were detected in the warming profiles from differential scanning calorimetry. VSL and its derivative, VSL+, seem to have the potential to be good alternatives to PVS2 for the cryopreservation of some materials, as exemplified by gentian buds. Mitsuteru Suzuki, Pramod Tandon and Masaya Ishikawa contributed equally to the work.     

Biosynthesis and therapeutic implications of iridoid glycosides from <Emphasis Type="Italic">Picrorhiza</Emphasis> genus: the road ahead

Picrorhiza genus is emerging as an important paradigm for herbal drug formulations due to its versatile iridoid glycosides exhibition and robustness in the treatment of diverse infections including hepatic amoebiasis, cancer, malaria, ulcerative colitis and cerebral ischemia reperfusion injury. Owing to the superiority of these bioactivities, iridoid glycosides from Picrorhiza have become a hot research area over the years. A metabolic pathway for the formation of iridoid glycosides has been proposed. However, some enzymes and genes of this route are still unidentified and demand the enumeration of facilitating pathways contributing to the biosynthesis of iridoid glycosides. This review summarizes the current knowledge of all naturally occurring iridoid glycosides from Picrorhiza, their biosynthesis and pharmacological capabilities which could provide the insight into metabolic regulation and the basis for the development of new drugs.     

Galvanic microparticles increase migration of human dermal fibroblasts in a wound-healing model via reactive oxygen species pathway

Electrical signals have been implied in many biological mechanisms, including wound healing, which has been associated with transient electrical currents not present in intact skin. One method to generate electrical signals similar to those naturally occurring in wounds is by supplementation of galvanic particles dispersed in a cream or gel. We constructed a three-layered model of skin consisting of human dermal fibroblasts in hydrogel (mimic of dermis), a hydrogel barrier layer (mimic of epidermis) and galvanic microparticles in hydrogel (mimic of a cream containing galvanic particles applied to skin). Using this model, we investigated the effects of the properties and amounts of Cu/Zn galvanic particles on adult human dermal fibroblasts in terms of the speed of wound closing and gene expression. The collected data suggest that the effects on wound closing are due to the ROS-mediated enhancement of fibroblast migration, which is in turn mediated by the BMP/SMAD signaling pathway. These results imply that topical low-grade electric currents via microparticles could enhance wound healing.     

Decorin biology, expression, function and therapy in the cornea

Decorin is a small leucine-rich proteoglycan (SLRP) that plays a vital role in many important cellular processes in several tissues including the cornea. A normal constituent of the corneal stroma, decorin is also found in the majority of connective tissues and is related structurally to other small proteoglycans. It interacts with various growth factors such as epidermal growth factor (EGF) and transforming growth factor beta (TGFβ) to regulate processes like collagen fibrillogenesis, extracellular matrix (ECM) compilation, and cell-cycle progression. Studies have linked decorin dysregulation to delayed tissue healing in patients with various diseases including cancer. In the cornea, decorin is involved in the regulation of transparency, a key function for normal vision. It has been reported that mutations in the decorin gene are associated with congenital stromal dystrophy, a disease that leads to corneal opacity and visual abnormalities. Decorin also antagonizes TGFβ in the cornea, a central regulatory cytokine in corneal wound healing. Following corneal injury, increased TGFβ levels induce keratocyte transdifferentiation to myofibroblasts and, subsequently, fibrosis (scarring) in the cornea. We recently reported that decorin overexpression in corneal fibroblasts blocks TGFβ-driven myofibroblast transformation and fibrosis development in the cornea in vitro suggesting that decorin gene therapy can be used for the treatment of corneal scarring in vivo.