Comparative macro- and micro-morphological studies on varieties ofParthenium argentatum Gray (guayule)

We investigated the leaf shape, venalion pattern, trichomes, stomata, and branching of the inflorescence axes in 15 varieties of guayule(Parthenium argentaturo Gray) growing in India. Working from our study objective, we were unable to identify any specific correlation between these macro- and micro-morphological characteristics and rubber content.     

Circular dichroism and Fourier transform infrared spectroscopic studies on self-assembly of tetrapeptide derivative in solution and solvated film.

Aggregation of the hydrophobic peptide derivative Boc-Ala-Ile-Ile-Gly-OMe (1) was examined in methanol solution and in solvated film states. Formation of the peptide by self-assembly was evidenced using fluorescence [Mg salt of 8-anilino-naphthalenesulfonic acid (ANS) as an external probe] and circular dichroism (CD) spectroscopic techniques. In solution, peptide 1 formed as a stable aggregate at a concentration around 3 x 10(-4)m. The peptide gelled into a thin film for which we carried out CD and Fourier transform infrared (FTIR) measurements. Our spectroscopic study on peptide films at differing methanol concentrations indicates that the helical content of the peptide decreases with decreasing methanol concentration in solvated films. However, by reducing the methanol concentration we were able to observe a conformational transition from a predominantly helical turn to a beta-sheet structure via a random coil conformation. Our study focused on the aggregation of the alpha-helical turn-forming peptide derivative, which shows conformational transition on changing solvent concentration in the film form.     

Role of N-t-Boc group in helix initiation in a novel tetrapeptide.

Protecting groups in N- and C-terminal positions play a decisive role in the conformational preference of smaller peptides. Conformational analysis of tetrapeptide derivatives containing Ala, Ile and Gly residues was performed. Peptide 1, Boc-Ala-Ile-Ile-Gly-OMe (Boc: tert-butyloxycarbonyl) has a predominantly helical turn conformation in all the alcoholic solvents studied, whereas in the solid state it has a beta-sheet conformation. In contrast, peptide 2, Ac-Ala-Ile-Ile-Gly-OMe (Ac: acetyl) has a random coil conformation in solution. The FTIR spectrum of peptide 1 shows a lower frequency of urethane carbonyl, indicating involvement of the carbonyl group in hydrogen bonding in the helical turn.     

Fabrication of chitin-chitosan/nano TiO2-composite scaffolds for tissue engineering applications

In this study, we prepared chitin-chitosan/nano TiO(2) composite scaffolds using lyophilization technique for bone tissue engineering. The prepared composite scaffold was characterized using SEM, XRD, FTIR and TGA. In addition, swelling, degradation and biomineralization capability of the composite scaffolds were evaluated. The developed composite scaffold showed controlled swelling and degradation when compared to the control scaffold. Cytocompatibility of the scaffold was assessed by MTT assay and cell attachment studies using osteoblast-like cells (MG-63), fibroblast cells (L929) and human mesenchymal stem cells (hMSCs). Results indicated no sign of toxicity and cells were found attached to the pore walls within the scaffolds. These results suggested that the developed composite scaffold possess the prerequisites for tissue engineering scaffolds and it can be used for tissue engineering applications.     

Role of Matricellular Proteins in Disorders of the Central Nervous System

Matricellular proteins (MCPs) are actively expressed non-structural proteins present in the extracellular matrix, which rapidly turnover and possess regulatory roles, as well as mediate cell–cell interactions. MCPs characteristically contain binding sites for other extracellular proteins, cell surface receptors, growth factors, cytokines and proteases, that provide structural support for surrounding cells. MCPs are present in most organs, including brain, and play a major role in cell–cell interactions and tissue repair. Among the MCPs found in brain include thrombospondin-1/2, secreted protein acidic and rich in cysteine family (SPARC), including Hevin/SC1, Tenascin C and CYR61/Connective Tissue Growth Factor/Nov family of proteins, glypicans, galectins, plasminogen activator inhibitor (PAI-1), autotaxin, fibulin and perisostin. This review summarizes the potential role of MCPs in the pathogenesis of major neurological disorders, including Alzheimer’s disease, amyotrophic lateral sclerosis, ischemia, trauma, hepatic encephalopathy, Down’s syndrome, autism, multiple sclerosis, brain neoplasms, Parkinson’s disease and epilepsy. Potential therapeutic opportunities of MCP’s for these disorders are also considered in this review.     

The effect of altered ergosterol content on the transport of various amino acids in Candida albicans.

Candida albicans cells have low levels of ergosterol when grown in ascorbic acid-supplemented media. When cells are grown in hydroquinone-supplemented media, the ergosterol levels became higher as compared to normal cells. The uptake of lysine, glycine, glutamic acid, proline, methionine and serine is reduced in hydroquinone-supplemented cells. In contrast to hydroquinone-supplemented cells, the rate and level of accumulation of these amino acids are higher in ascorbic acid-supplemented cells. Nystatin-resistant isolates of C. albicans with low ergosterol contents also exhibit an increased rate and level of accumulation of these amino acids. The uptake of phenylalanine and leucine remained unaffected by such a change in ergosterol levels brought about by different supplementation of the media. The results demonstrate a correlation between ergosterol levels and amino acids uptake. Contrary to various reports, the rate of K+ efflux does not seem to correlate with the amino acid uptake in C. albicans cells.     

Role of fibrillar Abeta25-35 in the inflammation induced rat model with respect to oxidative vulnerability

The major pathological ramification of Alzheimer's disease (AD) is accumulation of beta-Amyloid (Abeta) peptides in the brain. An emerging therapeutic approach for AD is elimination of excessive Ass peptides and preventing its re-accumulation. Immunization is the most effective strategy in removing preexisting cerebral Abetas and improving the cognitive capacity as shown in transgenic mice model of AD. However, active immunization is associated with adverse effect such as encephalitis with perivascular inflammation and hemorrhage. Details about the mechanistic aspects of propagation of these toxic effects are matter of intense enquiry as this knowledge is essential for the understanding of the AD pathophysiology. The present work aimed to study the oxidative vulnerability in the plasma, liver and brain of the inflammation-induced rats subjected to Ass immunization. Induction of inflammation was performed by subcutaneous injection of 0.5?ml of 2% silver nitrate. Our present result shows that the proinflammatory cytokines such as IL1alpha and TNFalpha are increased significantly in the inflammation-induced, Abeta1-42, Abeta25-35 treated groups and inflammation with Abeta25-35 treated group when compared to control, complete Freund's adjuvant and Abeta35-25 treated groups. These increased proinflammatory cytokines concurrently releases significant amount of free radicals in the astrocytes of respected groups. The present result shows that nitric oxide (NO) level was significantly higher (P<0.001) in plasma, liver and brain of the rat subjected to inflammation, Abeta1-42, Abeta25-35 and inflammation with Abeta25-35 injected groups when compared to control. The increased level of lipid peroxides (LPO) (P<0.001) and decreased antioxidant status (P<0.05) were observed in the plasma, liver and brain of inflammation-induced group when compared to control. Our result shows that significant oxidative vulnerability was observed in the inflammation with Ass treated rats when compared to other groups. Based on our results, we suggest that immunization of AD patients with Ass should be done with caution as the increase in Ass could trigger the brain inflammation in uncontrollable level.     

Global impairment of the ubiquitin-proteasome system by nuclear or cytoplasmic protein aggregates precedes inclusion body formation

The highly conserved ubiquitin-proteasome system (UPS) controls the stability of most nuclear and cytoplasmic proteins and is therefore essential for virtually all aspects of cellular function. We have previously shown that the UPS is impaired in the presence of aggregated proteins that become deposited into cytoplasmic inclusion bodies (IBs). Here, we report that production of protein aggregates specifically targeted to either the nucleus or cytosol leads to global impairment of UPS function in both cellular compartments and is independent of sequestration of aggregates into IBs. The observation of severe UPS impairment in compartments lacking detectable aggregates or aggregation-prone protein, together with the lack of interference of protein aggregates on 26S proteasome function in vitro, suggests that UPS impairment is unlikely to be a consequence of direct choking of proteasomes by protein aggregates. These data suggest a common proteotoxic mechanism for nuclear and cytoplasmic protein aggregates in the pathogenesis of neurodegenerative disease.     

The protective role of DL-α-lipoic acid in the oxidative vulnerability triggered by Aβ-amyloid vaccination in mice

Recent reports indicate that -amyloid peptide (A) vaccine based therapy for Alzheimers disease (AD) may be on the horizon. There are however, concerns about the safety of this approach. Immunization with A has several disadvantages, because it crosses the blood brain barrier and cause inflammation and neurotoxicity. The present work is aimed to study the protective effective of -lipoic acid (LA) in the oxidative vulnerability of -amyloid in plasma, liver, spleen and brain, when A fibrils are given intraperitoneally in inflammation induced mice. Result shows that reactive oxygen species (ROS) in the astrocytes of inflammation induced mice along with A (IA) has shown 2.5-fold increase when compared with LA treated mice. The increased level of lipid peroxidase (LPO) (p < 0.05) and decreased antioxidant status (p < 0.05) were observed in the plasma, liver, spleen and brain of IA induced mice when compared with LA treated mice.Data shows that there were no significant changes observed between the control and LA treated mice. Our biochemical and histological results highlight that significant oxidative vulnerability was observed in IA treated mice, which was prevented by LA therapy. Our findings suggest that the antioxidant effect of LA when induced with A may serve as a potent therapeutic tool for inflammatory AD models. (Mol Cell Biochem 270: 29–37, 2005)