Adenosine induced apoptosis in BHK cells via P1 receptors and equilibrative nucleoside transporters

Adenosine, as a ubiquitous metabolite, mediates many physiological functions via activation of plasma membrane receptors. Mechanisms of most of its physiological roles have been studied extensively, but research on adenosine-induced apoptosis (AIA) has only started recently. In this study we demonstrate that adenosine dose-dependently triggered apoptosis of cultured baby hamster kidney (BHK) cells. Adenosine-induced apoptotic cell death was characterized by DNA laddering, changes in nuclear chromatin morphology and phosphatidylserine staining. Apoptosis was also quantified by flow cytometry. Results suggest the involvement of adenosine A1 and A3 receptors as well as equilibrative nucleoside transporters in apoptosis induced by adenosine. These results indicate a receptor-transporter co-signaling mechanism in AIA in BHK cells. The involvement of A1 and A3 receptors also implies a possible apoptotic pathway mediated by G protein-coupled receptors.     

Grid cellware: the first grid-enabled tool for modelling and simulating cellular processes

Modelling and simulation of complex cellular transactions involve development of platforms that understand diverse mathematical representations and are capable of handling large backend computations. Grid Cellware, an integrated modelling and simulation tool, has been developed to precisely address these niche requirements of the modelling community. Grid Cellware implements various pathway simulation algorithms along with adaptive Swarm algorithm for parameter estimation. For enchanced computational productivity Grid Cellware uses grid technology with Globus as the middleware.     

New insights into the mechanism of gelation of alginate and pectin: charge annihilation and reversal mechanism

Studies have been undertaken on the binding of Mn2+ ions to two alginate samples of different mannuronate:guluronate ratios (M:G), a sample of low-ester amidated pectin and poly(acrylic acid) (PAA). The binding of Ca2+ ions has also been included for the latter for comparison. The binding curves showed an initial steep rise at low additions of Mn2+ or Ca2+ indicating that all of the ions were bound to the polymer chains with none remaining in solution. At higher additions, the binding curves showed a plateau region and the maximum amount bound, theta, was found to be 0.2, 0.2, 0.25, and 0.33 mol M(2+)/mol COO- for high M:G alginate, low M:G alginate, pectin, and PAA, respectively. The binding curves for Mn2+ and Ca2+ with PAA were superimposable. In all cases, theta was less than the stoichiometric equivalent and also less than predicted by Manning counterion condensation theory. The linear charge density, xi, for the polymers is 1.49, 1.55, 1.62, and 2.85, and it was found that at maximum binding the effective linear charge density, xi(effective), decreased to a value close to 1 in each case and not 0.5 as predicted from Manning's two-variable theory. The mobility of the PAA chains has been followed by electron spin resonance spectroscopy using nitroxide spin labels covalently attached to the polymer, and the gelation of the pectin and alginate samples has been monitored using small deformation oscillatory experiments. For PAA at maximum binding, it was noted that there was a loss of chain mobility and precipitation. For pectin and alginate, gelation occurred and the stoichiometric ratio for maximum binding corresponded to the stoichiometric ratio for the maximum in G'. Precipitation and gelation are attributed to the formation of polymer-metal complexes involving one or two carboxylate groups resulting in charge reversal or charge annihilation.     

The influence of chemical gustatory stimuli and oral anaesthesia on healthy human pharyngeal swallowing

This study explored the effects of taste and oral anaesthesia on human sequential swallowing. Subjects were healthy adults (n = 42, mean age 28 years, 21 females), investigated by means of a water swallow test. Taste stimuli comprised quinine, glucose, citrus and saline solutions compared with neutral water. Oral anaesthesia comprised topical lidocaine at doses of 10, 20 and 40 mg and compared with placebo. Data were collected on swallowing speed (volume per second), inter-swallow interval and swallowing capacity (volume per swallow). Compared with water, glucose, citrus and saline reduced swallowing speed (10.94 +/- 0.89 versus 9.56 +/- 0.79, 9.33 +/- 1.19, 9.37 +/- 0.92 ml/s respectively, P < 0.05). Inter-swallow interval was increased only by quinine and saline (1.47 +/- 1.11 versus 2.13 +/- 0.34 and 1.92 +/- 0.31 s, P < 0.04). Swallowing capacity was only marginally increased by quinine (P = 0.0759). Compared with the placebo, only 40 mg of lidocaine altered swallowing, immediately reducing the swallowing speed (7.89 +/- 2.34 versus 10.11 +/- 3.26 ml/s, P < 0.05) and increasing inter-swallow interval (1.67 +/- 0.38 versus 1.45 +/- 0.29 s, P < 0.01) without affecting capacity. By 15 min all measures except sensory thresholds had returned to baseline values. Thus, swallowing function is highly influenced by chemosensory input, providing insight into how oral sensation regulates pharyngeal swallowing.     

Molecular dissection of interspecific variation between Gossypium hirsutum and G. barbadense (cotton) by a backcross-self approach: II. Fiber fineness

A backcross-self population from a cross between Gossypium hirsutum and G. barbadense was used to dissect the molecular basis of genetic variation governing two parameters reflecting lint fiber fineness and to compare the precision of these two measurements. By applying a detailed restriction fragment length polymorphism (RFLP) map to 3,662 BC₃F₂ plants from 24 independently derived BC₃ families, we were able to detect 32 and nine quantitative trait loci (QTLs) for fiber fineness and micronaire (MIC), respectively. The discovery of larger numbers of QTLs in this study than previously found in other studies based on F₂ populations grown in favorable environments reflects the ability of the backcross-self design to resolve smaller QTL effects. Although the two measurements differed dramatically in the number of QTLs detected, seven of the nine MIC QTLs were also associated with fiber fineness. This supports other data in suggesting that fiber fineness more accurately reflects the underlying physical properties of cotton fibers and, consequently, is a preferable trait for selection. Negative transgression, with the majority of BC₃F₂ families showing average phenotypes that were poorer than that of the inferior parent, suggests that many of the new gene combinations formed by interspecific hybridization are maladaptive and may contribute to the lack of progress in utilizing G. barbadense in conventional breeding programs to improve upland cotton.Electronic Supplementary Material Supplementary material is available for this article at     

Development of photocatalytic biosensor for the evaluation of biochemical oxygen demand

The photocatalytic biosensor of flow system using semiconductor TiO2 was developed to evaluate biochemical oxygen demand (BOD) levels in river water. Photocatalysis of sample was carried out in a photoreactor with TiO2 and a 6W black-light blue fluorescent tube as light source. Sample from a photoreactor outlet was measured by an oxygen electrode with a biofilm. The sensor response of photocatalytic biosensor was between 5 and 10 min depending on concentration of biochemical in the samples. At BOD of 1 mgl-1, the sensor response increased 1.33-fold in comparison with that without photocatalysis. The degradation of tannic acid and humic acid with photocatalysis were 51.8 and 38.4%, respectively. Gum arabic and linear alkylbenzene sulfonate (LAS) were degraded a little, but gave the responses of more than double to the sensor. Free radicals yielded by photocatalysis in a photoreactor did not affect the sensor response because their lifetime is extremely short. Fairly good correlation (r=0.983) between the sensor method and the conventional method was obtained for test samples. This biosensor using photocatalytic pretreatment improved the sensitivity.     

Drosophila crinkled, mutations of which disrupt morphogenesis and cause lethality, encodes fly myosin VIIA

Myosin VIIs provide motor function for a wide range of eukaryotic processes. We demonstrate that mutations in crinkled (ck) disrupt the Drosophila myosin VIIA heavy chain. The ck/myoVIIA protein is present at a low level throughout fly development and at the same level in heads, thoraxes, and abdomens. Severe ck alleles, likely to be molecular nulls, die as embryos or larvae, but all allelic combinations tested thus far yield a small fraction of adult "escapers" that are weak and infertile. Scanning electron microscopy shows that escapers have defects in bristles and hairs, indicating that this motor protein plays a role in the structure of the actin cytoskeleton. We generate a homology model for the structure of the ck/myosin VIIA head that indicates myosin VIIAs, like myosin IIs, have a spectrin-like, SH3 subdomain fronting their N terminus. In addition, we establish that the two myosin VIIA FERM repeats share high sequence similarity with only the first two subdomains of the three-lobed structure that is typical of canonical FERM domains. Nevertheless, the approximately 100 and approximately 75 amino acids that follow the first two lobes of the first and second FERM domains are highly conserved among myosin VIIs, suggesting that they compose a conserved myosin tail homology 7 (MyTH7) domain that may be an integral part of the FERM domain or may function independently of it. Together, our data suggest a key role for ck/myoVIIA in the formation of cellular projections and other actin-based functions required for viability.     

Detection of insect Juvenile hormone III and Its precursors from<Emphasis Type="Italic">in Vitro</Emphasis> plantlets of<Emphasis Type="Italic">Cyperus aromaticus</Emphasis>

Juvenile hormone III (JH III) is one of the five closely related sesquiterpenoid compounds important in the regulation of an insect physiological processes in both the developing and the mature insect. JH III and its biosynthetic intermediates, farnesol and methyl farnesoate were detected in thein vitro Cyperus aromaticus plantlets and the mature plants growing in the field. A higher amount of methyl farnesoate (52.7%) and farnesol (31.4%) were found to be present in thein vitro plantlets as compared to the field grown mother plants which contained lower methyl farnesoate (19.5%) and farnesol (14.8%). On the other hand, the mature mother plant (4 months old) contained a higher percentage of JH III than thein vitro plantlets. The estimated content of JHIII analyzed by gas chromatography indicated that the amount of JHIII in the 10 weeks oldin vitro plantlets and the four months old mature plants of C.aromaticus was 0.076 μg/g and 0.085 μg/g respectively. This study indicated thatin vitro culture system could be a potential tool for the production of this natural derived bio-insecticide and could provide a material source for further investigations of the biosynthesis of JH III inC. aromaticus.